README: add warning about tags needing to start with v

This is a best practice thingie related to Dependabot updates and such for action runner references.

Includes allowing for [GitHub flavoured Markdown "alerts"](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts) in the README.

Author: jrfnl

.remarkrc

@@ -20,7 +20,18 @@
     "remark-lint-no-reference-like-url",
     "remark-lint-no-shortcut-reference-image",
     "remark-lint-no-table-indentation",
-    "remark-lint-no-undefined-references",
+    [
+        "remark-lint-no-undefined-references",
+        {
+            "allow": [
+                "!NOTE",
+                "!TIP",
+                "!IMPORTANT",
+                "!WARNING",
+                "!CAUTION"
+            ]
+        }
+    ],
     "remark-lint-no-unneeded-full-reference-image",
     "remark-lint-no-unneeded-full-reference-link",
     "remark-lint-no-unused-definitions",

README.md

@@ -66,6 +66,9 @@ This has two benefits:
 2. **Security**  
     With commit-hash pinned workflows, the dependencies used are fixed to specific versions and updates are managed, which means that it is more difficult for an attacker to be able to infiltrate the workflow runs and get access to secrets and/or cause other havoc.
 
+> [!IMPORTANT]  
+> It is best practice for tags for repositories which will be used in GitHub Actions workflows to be prefixed with `v` before the version number, so tags in this repository should start with a `v` prefix too.
+
 
 [community health files]: https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/creating-a-default-community-health-file