chore: Update to Go v1.21

- go mod tidy (all modules)
- go work sync
- Fixed plugin generation for Go 1.21
- Updated linting for Go 1.21
- Fixed minecraft example for Helm v3 pull download path
- Update dev docs to mention Go 1.21
- Regenerate plugins with Go 1.21

kyaml/fn/framework/command/command.go

@@ -121,7 +121,7 @@ func AddGenerateDockerfile(cmd *cobra.Command) {
 		Use:  "gen [DIR]",
 		Args: cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			if err := os.WriteFile(filepath.Join(args[0], "Dockerfile"), []byte(`FROM golang:1.20-alpine as builder
+			if err := os.WriteFile(filepath.Join(args[0], "Dockerfile"), []byte(`FROM golang:1.21-alpine as builder
 ENV CGO_ENABLED=0
 WORKDIR /go/src/
 COPY go.mod go.sum ./