CI: use GitHub actions with Docker to run tests

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: [tarleb, jgm]

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  pull_request:
+    branches:
+      - master
+    paths-ignore:
+      - '**/README.md'
+      - CONTRIBUTING.md
+      - LICENSE
+      - .editorconfig
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - '**/README.md'
+      - CONTRIBUTING.md
+      - LICENSE
+      - .editorconfig
+  schedule:
+    # At 4:17am each Monday
+    - cron: '17 4 * * 1'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Build Docker image
+        run: make docker-test-image
+
+      - name: Run tests in Docker image
+        run: make docker-test

Makefile

@@ -1,6 +1,6 @@
 FILTERS=$(wildcard $(shell find * -type d | grep -v '[/\\]'))
 FILTER_FILES=$(shell find * -name "*.lua" -type f)
-LUA_FILTERS_TEST_IMAGE = tarleb/lua-filters-test
+LUA_FILTERS_TEST_IMAGE = pandoc/lua-filters-test
 
 .PHONY: test show-args docker-test docker-test-image archive
 

README.md

@@ -25,8 +25,9 @@ Each filter goes in its own subdirectory.  Each subdirectory contains:
 Requirements
 ------------
 
-Filters are tested against the latest pandoc version.  There is
-no guarantee that filters will work with older versions, but
+Filters are tested against the pandoc version in the latest
+pandoc/ubuntu Docker image, i.e. usually the latest release. There
+is no guarantee that filters will work with older versions, but
 many do.
 
 Some filters depend on external programs, which must be installed