ci: add labels to issues created by sponsors

Closes #464

.github/ISSUE_TEMPLATE/bug_report.md

@@ -3,14 +3,14 @@ name: Bug report
 about: Create a report to help us improve
 ---
 
-## Description
+### Description
 
 <!--- Provide a more detailed introduction to the issue itself, and why you consider it to be a bug -->
 
-## Possible Fix
+### Possible Fix
 
 <!--- Not obligatory, but suggest a fix or reason for the bug -->
 
-## Checklist
+### Checklist
 
 - [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/HEAD/docs/contributing.md) document.

.github/ISSUE_TEMPLATE/custom.md

@@ -3,6 +3,6 @@ name: Custom issue template
 about: Describe this issue template's purpose here.
 ---
 
-## Checklist
+### Checklist
 
-- [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/master/docs/contributing.md) document.
+- [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/HEAD/docs/contributing.md) document.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -3,14 +3,14 @@ name: Feature request
 about: Suggest an idea for this project
 ---
 
-## Description
+### Description
 
 <!--- Provide a detailed description of the change or addition you are proposing -->
 
-## Possible Implementation
+### Possible Implementation
 
 <!--- Not obligatory, but suggest an idea for implementing addition or change -->
 
-## Checklist
+### Checklist
 
-- [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/master/docs/contributing.md) document.
+- [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/HEAD/docs/contributing.md) document.

.github/pull_request_template.md

@@ -1,16 +1,16 @@
-## Description
+### Description
 
 <!-- Describe your changes in detail and reference any issues it addresses-->
 
-## Checklist
+### Checklist
 
 <!-- Go over all the following points, and put an `x` in all the boxes that apply. -->
 
-- [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/master/docs/contributing.md) document.
+- [ ] I have read the [**contributing**](https://github.com/remirror/remirror/blob/HEAD/docs/contributing.md) document.
 - [ ] My code follows the code style of this project and `pnpm fix` completed successfully.
 - [ ] I have updated the documentation where necessary.
 - [ ] New code is unit tested and all current tests pass when running `pnpm test`.
 
-## Screenshots
+### Screenshots
 
 <!-- Delete this section if not applicable -->

.github/workflows/label-sponsors.yml

@@ -0,0 +1,15 @@
+name: Label sponsors
+
+on:
+  pull_request:
+    types: [opened]
+  issues:
+    types: [opened]
+
+jobs:
+  label_sponsors:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: JasonEtco/is-sponsor-label-action@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}