Switch linting to Github Actions

.github/workflows/lint.yaml

@@ -0,0 +1,25 @@
+name: Lint code
+
+on:
+  - push
+  - pull_request
+
+jobs:
+  mdl:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actionshub/markdownlint@main
+        name: Lint markdown files
+
+  vimlint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: vimlint
+        uses: tsuyoshicho/action-vimlint@v1
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          target: autoload plugin
+          fail_on_error: true
+          reporter: github-check

.mdl.rb

@@ -0,0 +1,4 @@
+all
+
+exclude_tag :line_length
+exclude_rule 'MD026' # trailing punctuation in header

.mdlrc

@@ -1,2 +1 @@
-rules "~MD013",
-      "~MD026"
+style '.mdl.rb'

README.md

@@ -1,10 +1,10 @@
+# Stay at my cursor, boy!
+
 [![Project status][badge-status]][vimscripts]
 [![Current release][badge-release]][releases]
 [![Open issues][badge-issues]][issues]
 [![License][badge-license]][license]
-[![Build Status][badge-build]][travis]
-
-# Stay at my cursor, boy!
+[![Lint status][badge-lint]][job-lint]
 
 *vim-stay* adds automated view session creation and restoration whenever editing a buffer, across Vim sessions and window life cycles. It also alleviates Vim's tendency to lose view state when cycling through buffers (via `argdo`, `bufdo` et al.). It is smart about which buffers should be persisted and which should not, making the procedure painless and invisible.
 
@@ -28,12 +28,12 @@ Keeping editing session state should be a given in an editor; unluckily, Vim's s
 
 *vim-stay* is licensed under [the terms of the MIT license according to the accompanying license file][license].
 
-[badge-status]:  http://img.shields.io/badge/status-maintained-green.svg?style=flat-square
-[badge-release]: http://img.shields.io/github/release/zhimsel/vim-stay.svg?style=flat-square
-[badge-issues]:  http://img.shields.io/github/issues/zhimsel/vim-stay.svg?style=flat-square
-[badge-license]: http://img.shields.io/badge/license-MIT-blue.svg?style=flat-square
-[badge-build]:   https://travis-ci.org/zhimsel/vim-stay.svg?branch=master
-[travis]:        https://travis-ci.org/zhimsel/vim-stay
+[badge-status]:  https://img.shields.io/badge/status-maintained-green.svg?style=flat-square
+[badge-release]: https://img.shields.io/github/release/zhimsel/vim-stay.svg?style=flat-square
+[badge-issues]:  https://img.shields.io/github/issues/zhimsel/vim-stay.svg?style=flat-square
+[badge-license]: https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square
+[badge-lint]:    https://img.shields.io/github/actions/workflow/status/zhimsel/vim-stay/lint.yaml?label=linting
+[job-lint]:      https://github.com/zhimsel/vim-stay/actions/workflows/lint.yaml
 [chao-plugin]:   http://www.vim.org/scripts/script.php?script_id=4021
 [doc]:           doc/vim-stay.txt
 [heuristics]:    https://github.com/zhimsel/vim-stay/issues/2