#4 : Implement Attach artifact to a release action

+ docs updated

README.md

@@ -13,7 +13,7 @@ The workflow (or jobs individually) needs to define an env variable `ACTI_BOT_TO
 Publishes a `generic` package to current Gitea instance. Example:
 
 ```yaml
-  - uses: https://source.vague.tech/open-vague/ci-actions/publish@feature/1-publish
+  - uses: https://source.vague.tech/open-vague/ci-actions/publish@master
     with:
       file: some-content.json
       package: the-package
@@ -26,7 +26,7 @@ Publishes a `generic` package to current Gitea instance. Example:
 * `version` - the package version, need to be unique (unless force flag is set)
 * `force` - false by default; if set **deletes the whole version** of the package (all files) and then publishes instead with the same version
 
-## Releasae
+## Release
 
 Create a tag and a release (if tag is not present) or a release for an existing tag.
 
@@ -34,7 +34,7 @@ The current implementation does not support moving tags, so version should be un
 
 ```yaml
   - id: create-release
-    uses: https://source.vague.tech/open-vague/ci-actions/release@feature/3-release
+    uses: https://source.vague.tech/open-vague/ci-actions/release@master
     with:
       name: Initial release
       version: v0.1.0
@@ -43,5 +43,21 @@ The current implementation does not support moving tags, so version should be un
 ```
 
 * `name` - release name
-* `body` - release notes (or description)
-* `version` - tag name
+* `body` - release notes (or description, optional)
+* `version` - tag name
+
+## Attach
+
+Attach an artefact file to an existing release. Important to know, the operation is not idempotent: if called twice will upload the file two times, creating two identical attachments.
+
+```yaml
+  - uses: https://source.vague.tech/open-vague/ci-actions/attach@master
+    with:
+      release: 142
+      name: Coverage report
+      file: cover.out
+```
+
+* `release` - release id (use the output `release_id` for the **release** action)
+* `file` - path to file
+* `name` - uploaded artefact name replacement (optional)