Update release to use Node.js v16 (ianstormtaylor#4879)

* Update release to use Node.js v16

* Update comment workflow to  Node.js v16

* Update ci.yml node config

* Fix slack invite link in issue template

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,5 @@
 blank_issues_enabled: false
 contact_links:
   - name: "💬 Support: Slack"
-    url: https://slate-slack.herokuapp.com/
+    url: https://join.slack.com/t/slate-js/shared_invite/zt-f8t986ip-7dA1DyiqPpzootz1snKXkw
     about: Please ask and answer questions in our Slack channel.

.github/workflows/ci.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Setup node
         uses: actions/setup-node@v2
         with:
-          node-version: 16
+          node-version: 16.x
           cache: yarn
           key: node16
 

.github/workflows/comment.yml

@@ -45,9 +45,10 @@ jobs:
       - name: Setup node
         uses: actions/setup-node@v2
         with:
-          node-version: 12.x
+          node-version: 16.x
           cache: yarn
           registry-url: https://registry.npmjs.org
+          key: node16
 
       - name: Install dependencies
         run: yarn

.github/workflows/release.yml

@@ -25,9 +25,10 @@ jobs:
       - name: Setup node
         uses: actions/setup-node@v2
         with:
-          node-version: 12.x
+          node-version: 16.x
           cache: yarn
           registry-url: https://registry.npmjs.org
+          key: node16
 
       - name: Install dependencies
         run: yarn