Chore: Move from master to main branch (#33693)

* Chore: Move from master branch to main

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

* CI: Upgrade build pipeline tool to v2

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/cmd/grafana-cli/main.go

@@ -13,7 +13,7 @@ import (
 	"github.com/urfave/cli/v2"
 )
 
-var version = "master"
+var version = "main"
 
 func main() {
 	setupLogging()

pkg/cmd/grafana-server/main.go

@@ -40,7 +40,7 @@ import (
 // The following variables cannot be constants, since they can be overridden through the -X link flag
 var version = "5.0.0"
 var commit = "NA"
-var buildBranch = "master"
+var buildBranch = "main"
 var buildstamp string
 
 type exitWithCode struct {