ci: remove travis, add GH Actions.

Author: ericonr

.github/workflows/ci.yaml

@@ -0,0 +1,17 @@
+name: Check PR
+on: pull_request
+
+jobs:
+  only:
+    name: Check formatting and links
+    runs-on: ubuntu-18.04
+    container:
+      image: ghcr.io/void-linux/void-linux:latest-full-x86_64-musl
+    steps:
+      - name: Prepare container
+        run: |
+          xbps-install -Syu || xbps-install -yu xbps
+          xbps-install -yu
+          xbps-install -y mdbook-linkcheck vmdfmt git
+      - uses: actions/checkout@v1
+      - run: ./res/ci/format.sh

.travis.yml

@@ -1,43 +1,12 @@
 #!/bin/sh
 
-echo "Installing mdbook-linkcheck"
-
-_version="v0.7.0"
-curl -sL -o ~/bin/linkcheck.tar.gz "https://github.com/Michael-F-Bryan/mdbook-linkcheck/releases/download/${_version}/mdbook-linkcheck-${_version}-x86_64-unknown-linux-gnu.tar.gz"
-
-tar xvf ~/bin/linkcheck.tar.gz -C ~/bin
+# Fetch upstream
+git fetch git://github.com/void-linux/void-docs.git master
 
 echo "Checking links"
-
-RUST_LOG=linkcheck=debug ~/bin/mdbook-linkcheck -s
+RUST_LOG=linkcheck=debug mdbook-linkcheck -s
 LINKCHECK=$?
 
-echo "Installing Go"
-
-curl -sL -o ~/bin/gimme https://raw.githubusercontent.com/travis-ci/gimme/master/gimme
-chmod +x ~/bin/gimme
-
-eval "$(gimme stable)"
-
-GO111MODULE=auto go get github.com/bobertlo/vmd/cmd/vmdfmt
-
-echo "Checking formatting"
-
-PATH=$PATH:$(go env GOPATH)/bin/
-
-if ! command -v git ; then
-    echo "You need git to run the CI scripts"
-    exit 1
-fi
-
-if ! command -v vmdfmt ; then
-    echo "You need vmdfmt to run the CI scripts"
-    exit 1
-fi
-
-# Fetch upstream
-git fetch git://github.com/void-linux/void-docs.git master
-
 # Format them
 printf "Formatting tree"
 vmdfmt -l -w src/