Update dump-logs README.md (#152)

Using without a tag results in the following error ``` the `uses' attribute must be a path, a Docker image, or owner/repo@ref ```
canonical · Sep 18, 2024 · 3952f8f · 3952f8f
1 parent 9341933
commit 3952f8f
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/dump-logs/README.md b/dump-logs/README.md
@@ -21,7 +21,7 @@ jobs:
       - name: Set up and run some tests
       - name: Dump logs
         if: failure()
-        uses: canonical/charming-actions/dump-logs
+        uses: canonical/charming-actions/dump-logs@2.6.3
 ```
 
 ## Known issues