Upgrade blang/semver from v3.5.0 to v4.0.0

v4.0.0 is fully compatible with Go Modules.

go.mod

@@ -5,7 +5,7 @@ go 1.14
 replace github.com/fluxcd/source-controller/api => ./api
 
 require (
-	github.com/blang/semver v3.5.0+incompatible
+	github.com/blang/semver/v4 v4.0.0
 	github.com/fluxcd/pkg/gittestserver v0.0.2
 	github.com/fluxcd/pkg/helmtestserver v0.0.1
 	github.com/fluxcd/pkg/lockedfile v0.0.5

go.sum

@@ -87,6 +87,8 @@ github.com/bitly/go-simplejson v0.5.0/go.mod h1:cXHtHw4XUPsvGaxgjIAn8PhEWG9NfngE
 github.com/blang/semver v3.1.0+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
 github.com/blang/semver v3.5.0+incompatible h1:CGxCgetQ64DKk7rdZ++Vfnb1+ogGNnB17OJKJXD2Cfs=
 github.com/blang/semver v3.5.0+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
+github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
+github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
 github.com/bmizerany/assert v0.0.0-20160611221934-b7ed37b82869 h1:DDGfHa7BWjL4YnC6+E63dPcxHo2sUxDIu8g3QgEJdRY=
 github.com/bmizerany/assert v0.0.0-20160611221934-b7ed37b82869/go.mod h1:Ekp36dRnpXw/yCqJaO+ZrUyxD+3VXMFFr56k5XYrpB4=
 github.com/bshuster-repo/logrus-logstash-hook v0.4.1 h1:pgAtgj+A31JBVtEHu2uHuEx0n+2ukqUJnS2vVe5pQNA=

internal/helm/repository.go

@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"io/ioutil"
 
-	"github.com/blang/semver"
+	"github.com/blang/semver/v4"
 	"helm.sh/helm/v3/pkg/repo"
 	"sigs.k8s.io/yaml"
 )

pkg/git/checkout.go

@@ -20,7 +20,7 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/blang/semver"
+	"github.com/blang/semver/v4"
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"