add linting in CI + fix lint errors (#473)

* run `yarn lint --fix`

* Revert "Revert "add linting to ci""

This reverts commit 0bbbbee4be.

* Fixed some errors

* remove unused code - not sure why this was here?

* assert env var

* more type fixes

* fix typings og gcal callback - needs testing

* rename `md5.ts` to `md5.js`

it is js.

* fix types

* fix types

* fix lint errors

* fix last lint error

Co-authored-by: Alex van Andel <me@alexvanandel.com>

.github/workflows/lint.yml

@@ -0,0 +1,21 @@
+name: Lint
+on: [push]
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: Use Node.js 14.x
+        uses: actions/setup-node@v1
+        with:
+          version: 14.x
+
+      - name: Install deps
+        uses: bahmutov/npm-install@v1
+
+      - name: Lint
+        run: yarn lint