Add shellcheck and Markdownlint

.github/workflows/markdownlint.yaml

@@ -0,0 +1,16 @@
+name: Lint Markdown Files
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+      - name: Run linter
+        uses: actionshub/markdownlint@main

.github/workflows/shellcheck.yaml

@@ -0,0 +1,14 @@
+name: shellcheck
+
+on:
+  - push
+  - pull_request
+
+jobs:
+  shellcheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Run shellcheck
+        uses: ludeeus/action-shellcheck@master

README.md

@@ -1,2 +1,3 @@
-# rubin_workflows 
+# rubin_workflows
+
 Workflows for GitHub Actions.