migrate dgrijalva/jwt-go to golang-jwt/jwt-go

[shogo82148]

github.com/dgrijalva/jwt-go is no longer maintained.

/~https://github.com/dgrijalva/jwt-go#readme says:

THIS REPOSITORY IS NO LONGER MAINTANED
The new repository can be found at: /~https://github.com/golang-jwt/jwt

For more information, see issue #462.

it recommends to migrate to /~https://github.com/golang-jwt/jwt

[SVilgelm]

Fixes #54

[shogo82148]

memo: Int.FillBytes was added in Go 1.15.

/~https://github.com/bradleyfalzon/ghinstallation/pull/53/checks?check_run_id=3582316698#step:5:12

# github.com/golang-jwt/jwt/v4
Error: ../../../go/pkg/mod/github.com/golang-jwt/jwt/v4@v4.0.0/ecdsa.go:135:4: r.FillBytes undefined (type *big.Int has no field or method FillBytes)
Error: ../../../go/pkg/mod/github.com/golang-jwt/jwt/v4@v4.0.0/ecdsa.go:136:4: s.FillBytes undefined (type *big.Int has no field or method FillBytes)
note: module requires Go 1.15

[bradleyfalzon]

@shogo82148 are you able to resolve the conflict with master? Apologies for this.

[shogo82148]

@bradleyfalzon I did.

[torstenwalter]

@bradleyfalzon could you have another look?

[bradleyfalzon]

Looks good, just on mobile and will need to tag once I get near a computer

[markushinz]

@bradleyfalzon could you create new release?

[bradleyfalzon]

Apologies, released