docs: add example for latest tag with dynamic condition

As described in https://github.com/docker/metadata-action/issues/147 Signed-off-by: Stig Otnes Kolstad <stig@stigok.com>
docker · Jan 14, 2022 · 5949fa2 · 5949fa2
1 parent e562237
commit 5949fa2
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diff --git a/README.md b/README.md
@@ -605,6 +605,14 @@ tags: |
 * [`type=semver,pattern=...`](#typesemver)
 * [`type=match,pattern=...`](#typematch)
 
+For conditionally tagging with latest for a specific branch name, e.g. if your default branch name
+is not `master`, use `type=raw` with a boolean expression:
+
+```yaml
+tags: |
+  type=raw,value=latest,enable=${{ endsWith(github.ref, github.event.repository.default_branch) }}
+```
+
 ### Global expressions
 
 The following [Handlebars template](https://handlebarsjs.com/guide/) expressions for `prefix`, `suffix` and `value`