refactor: manually modernize Go (#349)

Signed-off-by: Miek Gieben <miek@miek.nl>

internal/machine/caddyconfig/controller.go

@@ -242,8 +242,8 @@ func (c *Controller) writeCaddyfileIfChanged(caddyfile string) error {
 // caddyfileBody returns the Caddyfile content without its first line, which carries a generation timestamp that
 // rotates on every regeneration.
 func caddyfileBody(caddyfile string) string {
-	if i := strings.IndexByte(caddyfile, '\n'); i >= 0 {
-		return caddyfile[i+1:]
+	if _, after, ok := strings.Cut(caddyfile, "\n"); ok {
+		return after
 	}
 	return caddyfile
 }

internal/machine/caddyconfig/controller_test.go

@@ -30,8 +30,7 @@ func TestContainerFingerprint_EqualCoversAllFields(t *testing.T) {
 	assert.True(t, base.Equal(base), "base fingerprint must be equal to itself")
 
 	rt := reflect.TypeOf(base)
-	for i := 0; i < rt.NumField(); i++ {
-		field := rt.Field(i)
+	for field := range rt.Fields() {
 		t.Run(field.Name, func(t *testing.T) {
 			t.Parallel()
 

internal/machine/caddyconfig/mocks_test.go

@@ -62,7 +62,7 @@ type MockCaddyfileValidator_Validate_Call struct {
 // Validate is a helper method to define mock.On call
 //   - ctx context.Context
 //   - caddyfile string
-func (_e *MockCaddyfileValidator_Expecter) Validate(ctx interface{}, caddyfile interface{}) *MockCaddyfileValidator_Validate_Call {
+func (_e *MockCaddyfileValidator_Expecter) Validate(ctx any, caddyfile any) *MockCaddyfileValidator_Validate_Call {
 	return &MockCaddyfileValidator_Validate_Call{Call: _e.mock.On("Validate", ctx, caddyfile)}
 }