Simplify code spell CI system

Now that the parser tool is moved out of the repository, it makes less sense to use the taskfile-based approach for the
CI infrastructure. In order to make the repository more contributor-friendly, the spell checking system is now reduced to
a single workflow file.

.github/workflows/spell-check.yml

@@ -10,6 +10,8 @@ on:
   schedule:
     # Run every Tuesday at 03:00 UTC to catch breakage caused by updates to the dictionary
     - cron: "0 3 * * 2"
+  workflow_dispatch:
+  repository_dispatch:
 
 jobs:
   spellcheck:
@@ -19,19 +21,12 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
 
-      - name: Install Python
-        uses: actions/setup-python@v2
-        with:
-          python-version: "3.8"
-
-      - name: Install Poetry
-        run: pip install poetry
-
-      - name: Install Taskfile
-        uses: arduino/actions/setup-taskfile@master
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
-          version: 3.x
-
       - name: Spell check
-        run: task check-spelling
+        uses: codespell-project/actions-codespell@master
+        with:
+          # In the event of a false positive, add the problematic word, in all lowercase, to a comma-separated list here:
+          ignore_words_list:
+          builtin: clear,informal,en-GB_to_en-US
+          check_filenames: true
+          check_hidden: true
+          skip: ./.git,./repositories.txt