Add CI workflow to check for commonly misspelled words

On every push, pull request, and periodically, use the codespell-project/actions-codespell action to check for commonly
misspelled words.

In the event of a false positive, the problematic word should be added, in all lowercase, to the ignore-words-list field
of ./.codespellrc. Regardless of the case of the word in the false positive, it must be in all lowercase in the ignore
list. The ignore list is comma-separated with no spaces.

Author: per1234

.codespellrc

@@ -0,0 +1,6 @@
+[codespell]
+# In the event of a false positive, add the problematic word, in all lowercase, to a comma-separated list here:
+ignore-words-list = ,
+check-filenames =
+check-hidden =
+skip = ./.git

.github/workflows/spell-check.yml

@@ -0,0 +1,24 @@
+name: Spell Check
+
+on:
+  pull_request:
+  push:
+  schedule:
+    # Run every Saturday at 3 AM UTC to catch new misspelling detections resulting from dictionary updates.
+    - cron: "0 3 * * 6"
+  # See: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows#workflow_dispatch
+  workflow_dispatch:
+  # See: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows#repository_dispatch
+  repository_dispatch:
+
+jobs:
+  spellcheck:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      # See: https://github.com/codespell-project/actions-codespell/blob/master/README.md
+      - name: Spell check
+        uses: codespell-project/actions-codespell@master

README.adoc

@@ -1,4 +1,10 @@
-= ArduinoECCX08 =
+// Define the repository information in these attributes
+:repository-owner: arduino-libraries
+:repository-name: ArduinoECCX08
+
+= {repository-name} =
+
+image:https://github.com/{repository-owner}/{repository-name}/workflows/Spell%20Check/badge.svg["Spell Check Status", link="https://github.com/{repository-owner}/{repository-name}/actions?workflow=Spell+Check"]
 
 Arduino Library for the Atmel/Microchip ECC508 and ECC608 crypto chips