Update push_rules/push_rules.md

Fix wrong tier and remove redundant tiers

doc/push_rules/push_rules.md

@@ -73,7 +73,7 @@ Some example regular expressions you can use in push rules:
 By default, GitLab restricts certain formats of branch names for security purposes.
 40-character hexadecimal names, similar to Git commit hashes, are prohibited.
 
-### Custom Push Rules **(FREE SELF)**
+### Custom Push Rules **(PREMIUM SELF)**
 
 It's possible to create custom push rules rather than the push rules available in
 **Admin Area > Push Rules** by using more advanced server hooks.
@@ -104,8 +104,8 @@ The following options are available:
 |---------------------------------|-------------|
 | Removal of tags with `git push` | Forbid users to remove Git tags with `git push`. Tags can be deleted through the web UI. |
 | Check whether the commit author is a GitLab user | Restrict commits to existing GitLab users (checked against their emails). |
-| Reject unverified users **(PREMIUM)** | GitLab rejects any commit that was not committed by an authenticated user. |
-| Check whether commit is signed through GPG **(PREMIUM)** | Reject commit when it is not signed through GPG. Read [signing commits with GPG](../user/project/repository/gpg_signed_commits/index.md). |
+| Reject unverified users | GitLab rejects any commit that was not committed by an authenticated user. |
+| Check whether commit is signed through GPG | Reject commit when it is not signed through GPG. Read [signing commits with GPG](../user/project/repository/gpg_signed_commits/index.md). |
 | Prevent pushing secret files | GitLab rejects any files that are likely to contain secrets. See the [forbidden file names](#prevent-pushing-secrets-to-the-repository). |
 | Require expression in commit messages | Only commit messages that match this regular expression are allowed to be pushed. Leave empty to allow any commit message. Uses multiline mode, which can be disabled using `(?-m)`. |
 | Reject expression in commit messages | Only commit messages that do not match this regular expression are allowed to be pushed. Leave empty to allow any commit message. Uses multiline mode, which can be disabled using `(?-m)`. |
@@ -117,7 +117,7 @@ The following options are available:
 NOTE:
 GitLab uses [RE2 syntax](https://github.com/google/re2/wiki/Syntax) for regular expressions in push rules, and you can test them at the [regex101 regex tester](https://regex101.com/).
 
-### Caveat to "Reject unsigned commits" push rule **(PREMIUM)**
+### Caveat to "Reject unsigned commits" push rule
 
 This push rule ignores commits that are authenticated and created by GitLab
 (either through the UI or API). When the **Reject unsigned commits** push rule is