fix: link update for README.md for v4 (#217)

Co-authored-by: Christian Banse <[email protected]>

README.md

@@ -54,9 +54,9 @@ import "github.com/golang-jwt/jwt/v4"
 
 See [the project documentation](https://pkg.go.dev/github.com/golang-jwt/jwt/v4) for examples of usage:
 
-* [Simple example of parsing and validating a token](https://pkg.go.dev/github.com/golang-jwt/jwt#example-Parse-Hmac)
-* [Simple example of building and signing a token](https://pkg.go.dev/github.com/golang-jwt/jwt#example-New-Hmac)
-* [Directory of Examples](https://pkg.go.dev/github.com/golang-jwt/jwt#pkg-examples)
+* [Simple example of parsing and validating a token](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#example-Parse-Hmac)
+* [Simple example of building and signing a token](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#example-New-Hmac)
+* [Directory of Examples](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#pkg-examples)
 
 ## Extensions
 
@@ -110,10 +110,10 @@ Asymmetric signing methods, such as RSA, use different keys for signing and veri
 
 Each signing method expects a different object type for its signing keys. See the package documentation for details. Here are the most common ones:
 
-* The [HMAC signing method](https://pkg.go.dev/github.com/golang-jwt/jwt#SigningMethodHMAC) (`HS256`,`HS384`,`HS512`) expect `[]byte` values for signing and validation
-* The [RSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt#SigningMethodRSA) (`RS256`,`RS384`,`RS512`) expect `*rsa.PrivateKey` for signing and `*rsa.PublicKey` for validation
-* The [ECDSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt#SigningMethodECDSA) (`ES256`,`ES384`,`ES512`) expect `*ecdsa.PrivateKey` for signing and `*ecdsa.PublicKey` for validation
-* The [EdDSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt#SigningMethodEd25519) (`Ed25519`) expect `ed25519.PrivateKey` for signing and `ed25519.PublicKey` for validation
+* The [HMAC signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodHMAC) (`HS256`,`HS384`,`HS512`) expect `[]byte` values for signing and validation
+* The [RSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodRSA) (`RS256`,`RS384`,`RS512`) expect `*rsa.PrivateKey` for signing and `*rsa.PublicKey` for validation
+* The [ECDSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodECDSA) (`ES256`,`ES384`,`ES512`) expect `*ecdsa.PrivateKey` for signing and `*ecdsa.PublicKey` for validation
+* The [EdDSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodEd25519) (`Ed25519`) expect `ed25519.PrivateKey` for signing and `ed25519.PublicKey` for validation
 
 ### JWT and OAuth
 
@@ -131,7 +131,7 @@ This library uses descriptive error messages whenever possible. If you are not g
 
 ## More
 
-Documentation can be found [on pkg.go.dev](https://pkg.go.dev/github.com/golang-jwt/jwt).
+Documentation can be found [on pkg.go.dev](https://pkg.go.dev/github.com/golang-jwt/jwt/v4).
 
 The command line utility included in this project (cmd/jwt) provides a straightforward example of token creation and parsing as well as a useful tool for debugging your own integration. You'll also find several implementation examples in the documentation.