Use Go standard library errors package (#45)

Replace the deprecated and archived `github.com/pkg/errors` package with
the Go standard library `errors` package and `%w` wrapping so it can be
used with `errors.Is()`.
* Bump minimum Go version to 1.19 to automatically include transitive
  dependencies in the Go modules files.

Signed-off-by: SuperQ <superq@gmail.com>

go.mod

@@ -1,9 +1,14 @@
 module github.com/lestrrat-go/strftime
 
-go 1.13
+go 1.19
 
 require (
 	github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc
-	github.com/pkg/errors v0.9.1
 	github.com/stretchr/testify v1.8.4
 )
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -1,21 +1,12 @@
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc h1:RKf14vYWi2ttpEmkA4aQ3j4u9dStX2t4M8UM6qqNsG8=
 github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc/go.mod h1:kopuH9ugFRkIXf3YoqHKyrJ9YfUFsckUU9S7B+XP+is=
-github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

specifications.go

@@ -1,10 +1,9 @@
 package strftime
 
 import (
+	"errors"
 	"fmt"
 	"sync"
-
-	"github.com/lestrrat-go/strftime/internal/errors"
 )
 
 // because there is no such thing was a sync.RWLocker
@@ -124,7 +123,7 @@ func (ds *specificationSet) Lookup(b byte) (Appender, error) {
 	}
 	v, ok := ds.store[b]
 	if !ok {
-		return nil, errors.Errorf(`lookup failed: '%%%c' was not found in specification set`, b)
+		return nil, fmt.Errorf(`lookup failed: '%%%c' was not found in specification set`, b)
 	}
 	return v, nil
 }

strftime.go

@@ -1,12 +1,12 @@
 package strftime
 
 import (
+	"errors"
+	"fmt"
 	"io"
 	"strings"
 	"sync"
 	"time"
-
-	"github.com/lestrrat-go/strftime/internal/errors"
 )
 
 type compileHandler interface {
@@ -62,7 +62,7 @@ func compile(handler compileHandler, p string, ds SpecificationSet) error {
 
 		specification, err := ds.Lookup(p[1])
 		if err != nil {
-			return errors.Wrap(err, `pattern compilation failed`)
+			return fmt.Errorf("pattern compilation failed: %w", err)
 		}
 
 		handler.handle(specification)
@@ -127,14 +127,14 @@ func Format(p string, t time.Time, options ...Option) (string, error) {
 	// TODO: this may be premature optimization
 	ds, err := getSpecificationSetFor(options...)
 	if err != nil {
-		return "", errors.Wrap(err, `failed to get specification set`)
+		return "", fmt.Errorf("failed to get specification set: %w", err)
 	}
 	h := getFmtAppendExecutor()
 	defer releasdeFmtAppendExecutor(h)
 
 	h.t = t
 	if err := compile(h, p, ds); err != nil {
-		return "", errors.Wrap(err, `failed to compile format`)
+		return "", fmt.Errorf("failed to compile format: %w", err)
 	}
 
 	return string(h.dst), nil
@@ -152,14 +152,14 @@ func New(p string, options ...Option) (*Strftime, error) {
 	// TODO: this may be premature optimization
 	ds, err := getSpecificationSetFor(options...)
 	if err != nil {
-		return nil, errors.Wrap(err, `failed to get specification set`)
+		return nil, fmt.Errorf("failed to get specification set: %w", err)
 	}
 
 	var h appenderListBuilder
 	h.list = &combiningAppend{}
 
 	if err := compile(&h, p, ds); err != nil {
-		return nil, errors.Wrap(err, `failed to compile format`)
+		return nil, fmt.Errorf("failed to compile format: %w", err)
 	}
 
 	return &Strftime{