feat: use Git notes to store the channels on which a version has been released

BREAKING CHANGE: this feature change the way semantic-release keep track of the channels on which a version has been released.
It now use a JSON object stored in a [Git note](https://git-scm.com/docs/git-notes) instead of Git tags formatted as v{version}@{channel}.

The tags formatted as v{version}@{channel} will now be ignored. If you have made releases with v16.0.0 on branches other than the default one you will have to update your repository.

The changes to make consist in:
- Finding all the versions that have been released on a branch other than the default one by searching for all tags formatted v{version}@{channel}
- For each of those version:
  - Create a tag without the {@channel} if none doesn't already exists
  - Add a Git note to the tag without the {@channel} containing the channels on which the version was released formatted as `{"channels":["channel1","channel2"]}` and using `null` for the default channel (for example.`{"channels":[null,"channel1","channel2"]}`)
  - Push the tags and notes
  - Update the GitHub releases that refer to a tag formatted as v{version}@{channel} to use the tag without it
  - Delete the tags formatted as v{version}@{channel}

test/helpers/git-utils.js

@@ -4,6 +4,7 @@ import fileUrl from 'file-url';
 import pEachSeries from 'p-each-series';
 import gitLogParser from 'git-log-parser';
 import getStream from 'get-stream';
+import {GIT_NOTE_REF} from '../../lib/definitions/constants';
 
 /**
  * Commit message informations.
@@ -258,3 +259,24 @@ export async function mergeFf(ref, execaOpts) {
 export async function rebase(ref, execaOpts) {
   await execa('git', ['rebase', ref], execaOpts);
 }
+
+/**
+ * Add a note to a Git reference.
+ *
+ * @param {String} note The note to add.
+ * @param {String} ref The ref to add the note to.
+ * @param {Object} [execaOpts] Options to pass to `execa`.
+ */
+export async function gitAddNote(note, ref, execaOpts) {
+  await execa('git', ['notes', '--ref', GIT_NOTE_REF, 'add', '-m', note, ref], execaOpts);
+}
+
+/**
+ * Get the note associated with a Git reference.
+ *
+ * @param {String} ref The ref to get the note from.
+ * @param {Object} [execaOpts] Options to pass to `execa`.
+ */
+export async function gitGetNote(ref, execaOpts) {
+  return (await execa('git', ['notes', '--ref', GIT_NOTE_REF, 'show', ref], execaOpts)).stdout;
+}