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_test.go

@@ -41,7 +41,7 @@ func TestCommand_dockerfile(t *testing.T) {
 		t.FailNow()
 	}
 
-	expected := `FROM golang:1.20-alpine as builder
+	expected := `FROM golang:1.21-alpine as builder
 ENV CGO_ENABLED=0
 WORKDIR /go/src/
 COPY go.mod go.sum ./