style: format code with Gofumpt and Prettier

This commit fixes the style issues introduced in e709f16 according to the output
from Gofumpt and Prettier.

Details: #2595

hack/actions/gen/main.go

@@ -282,7 +282,7 @@ func generateWorkflowStruct(data *Data) Workflow {
 }
 
 func initializeData(data *Data) {
-	var pullRequestPaths = make([]string, 0) // TODO: ContainerTypeごとなどいろいろ条件分岐
+	pullRequestPaths := make([]string, 0) // TODO: ContainerTypeごとなどいろいろ条件分岐
 
 	data.PushBranches = []string{"main", "release/v*.*", "!release/v*.*.*"}
 	data.PushTags = []string{"*.*.*", "v*.*.*", "*.*.*-*", "v*.*.*-*"}