Added changelog

changelogs/unreleased/36859-update-gpg-docs-with-gpg2.yml

+---
+title: Update gpg documentation with gpg2
+merge_request: 13851
+author: M M Arif
+type: other

doc/user/project/repository/gpg_signed_commits/index.md

@@ -30,6 +30,16 @@ to be met:
 
 ## Generating a GPG key
 
+>**Notes:**
+- If your Operating System has `gpg2` installed, replace `gpg` with `gpg2` in
+  the following commands.
+- If Git is using `gpg` and you get errors like `secret key not available` or
+  `gpg: signing failed: secret key not available`, run the following command to
+  change to `gpg2`:
+    ```
+    git config --global gpg.program gpg2
+    ```
+
 If you don't already have a GPG key, the following steps will help you get
 started: