Migrate from Travis CI to GitLab CI.

Also, update pre-commit hooks.

.gitlab-ci.yml

+---
+stages:
+  - test
+
+pre-commit:
+  stage: test
+  image: adarnimrod/ci-images:pre-commit
+  variables:
+    XDG_CACHE_HOME: "$CI_PROJECT_DIR/.cache"
+  script:
+    - pre-commit run --all-files
+  cache:
+    paths:
+      - .cache/
+
+test:
+  stage: test
+  image: buildpack-deps:bullseye
+  allow_failure: true
+  before_script:
+    - apt-get update
+    - apt-get install -y bats
+  script:
+    - bats .

.pre-commit-config.yaml

+---
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    sha: v1.2.3
+    rev: v3.4.0
     hooks:
       - id: check-added-large-files
-    -   id: check-yaml
+      - id: check-executables-have-shebangs
       - id: check-merge-conflict
-    -   id: check-symlinks
-    -   id: detect-private-key
       - id: trailing-whitespace
+
   - repo: https://github.com/adarnimrod/shell-pre-commit
-    sha: v0.6.0
+    rev: v0.6.0
     hooks:
       - id: shell-lint
       - id: shellcheck
+
+  - repo: https://github.com/myint/rstcheck
+    rev: master
+    hooks:
+      - id: rstcheck
+
+  - repo: https://github.com/adrienverge/yamllint
+    rev: v1.25.0
+    hooks:
+      - id: yamllint

README.rst

 bundle-certs
 ############
 
-.. image:: https://travis-ci.org/adarnimrod/bundle_certs.svg?branch=master
-    :target: https://travis-ci.org/adarnimrod/bundle_certs
+.. image:: https://git.shore.co.il/nimrod/bundle_certs/badges/master/pipeline.svg
+    :target: https://git.shore.co.il/nimrod/bundle_certs/-/commits/master
+    :alt: pipeline status
 
 A shell script to bundle SSL certificates in the correct order. The use case
 envisioned is programmatically handling SSL certificate renewal.
@@ -28,8 +29,8 @@ For regular use:
 
 For testing/ development purposes, all of the above, plus:
 
-- `Bats <https://github.com/sstephenson/bats>`_.
-- `Pre-commit <http://pre-commit.com/>`_.
+- Bats_
+- Pre-commit_
 
 Usage
 -----
@@ -61,9 +62,8 @@ Shell functions
 Development and testing
 -----------------------
 
-Testing is done using Bats <https://github.com/sstephenson/bats>`_. To test run
-:code:`bats test.bats`. `Pre-commit <http://pre-commit.com/>`_ is also
-configured for this repo.
+Testing is done using Bats_. To test run :code:`bats test.bats`. Pre-commit_ is
+also configured for this repo.
 
 License
 -------
@@ -77,4 +77,7 @@ Author Information
 Nimrod Adar, `contact me <nimrod@shore.co.il>`_ or visit my `website
 <https://www.shore.co.il/>`_. Patches are welcome via `git send-email
 <http://git-scm.com/book/en/v2/Git-Commands-Email>`_. The repository is located
-at: https://www.shore.co.il/cgit/.
+at: https://git.shore.co.il/explore/.
+
+.. _Bats: https://github.com/sstephenson/bats
+.. _Pre-commit: https://pre-commit.com/

test.bats

-#!/usr/bin/env bats
-
 setup () {
     teardown
     mkdir -p .testcerts