ci: add markdownlint

Author: gadomski

.github/pull_request_template.md

@@ -24,3 +24,5 @@ Delete any checklist items that do not apply (e.g. if your change is minor, it m
 - [ ] Code is formatted (`cargo fmt`)
 - [ ] `cargo test`
 - [ ] Changes are added to the CHANGELOG
+
+<!-- markdownlint-disable-file MD041 -->

.github/workflows/ci.yml

@@ -201,6 +201,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: Swatinem/rust-cache@v2
+      - uses: DavidAnson/markdownlint-cli2-action@v9
       - name: Doc
         run: cargo doc --workspace --all-features
   validate-stac-geoparquet:

.markdownlint-cli2.jsonc

@@ -0,0 +1,8 @@
+{
+    "config": {
+        "MD013": false
+    },
+    "globs": ["**/*.md"],
+    "gitignore": true,
+    "ignores": ["spec-examples/*/README.md", "crates/*/examples/README.md", "python/examples/README.md", "target/**/*.md"]
+}