Add /v2 suffix to module name in preparation of 2.0.0 release

Signed-off-by: Max Jonas Werner <mail@makk.es>

internal/flags/log_level.go

@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/fluxcd/flux2/internal/utils"
+	"github.com/fluxcd/flux2/v2/internal/utils"
 )
 
 var supportedLogLevels = []string{"debug", "info", "error"}