feat: add --skip-diff-validation-on-install CLI flag (#2728)

Signed-off-by: Richter <h.richter@sap.com>

pkg/config/diff.go

@@ -22,6 +22,8 @@ type DiffOptions struct {
 	EnforceNeedsAreInstalled bool
 	// SkipDiffOnInstall is the skip diff on install flag
 	SkipDiffOnInstall bool
+	// SkipDiffValidationOnInstall disables K8s API validation when running helm-diff on a release being newly installed
+	SkipDiffValidationOnInstall bool
 	// ShowSecrets is the show secrets flag
 	ShowSecrets bool
 	// NoHooks skips hooks during diff
@@ -168,6 +170,11 @@ func (t *DiffImpl) SkipDiffOnInstall() bool {
 	return t.DiffOptions.SkipDiffOnInstall
 }
 
+// SkipDiffValidationOnInstall returns the skip diff validation on install
+func (t *DiffImpl) SkipDiffValidationOnInstall() bool {
+	return t.DiffOptions.SkipDiffValidationOnInstall
+}
+
 // DiffArgs returns the list of arguments to pass to helm-diff.
 func (t *DiffImpl) DiffArgs() string {
 	return t.DiffOptions.DiffArgs