Update CI configuration

Remove Travis CI + EVM which are slow and problematic.

* .github/workflows/test.yml: Run CI also for PRs and with the
latest Emacs release and Checkout Action versions.
* .travis.yml:
* run-travis-ci.sh: Remove files.

Re: #328.

.github/workflows/test.yml

@@ -1,5 +1,5 @@
 name: CI
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
@@ -18,12 +18,13 @@ jobs:
           - '26.1'
           - '26.2'
           - '26.3'
+          - '27.1'
           - 'snapshot'
         include:
           - emacs_version: 'snapshot'
             allow_failure: true
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - uses: purcell/setup-emacs@master
       with:
         version: ${{ matrix.emacs_version }}

.travis.yml

@@ -1,18 +0,0 @@
-language: emacs-lisp
-sudo: no
-env:
- - EVM_EMACS=emacs-24.1-travis
- - EVM_EMACS=emacs-24.2-travis
- - EVM_EMACS=emacs-24.3-travis
- - EVM_EMACS=emacs-24.4-travis
- - EVM_EMACS=emacs-24.5-travis
- - EVM_EMACS=emacs-25.1-travis
- - EVM_EMACS=emacs-25.2-travis
- - EVM_EMACS=emacs-25.3-travis
- - EVM_EMACS=emacs-26.1-travis
- - EVM_EMACS=emacs-git-snapshot-travis
-install:
-  - curl -fsSkL https://gist.github.com/rejeep/ebcd57c3af83b049833b/raw > travis.sh && source ./travis.sh
-  - evm install $EVM_EMACS --use --skip
-script:
-  ./run-travis-ci.sh

run-travis-ci.sh

@@ -1,20 +0,0 @@
-#!/bin/sh
-
-cd "$(dirname "$0")"
-
-set_default () {
-  eval "
-if [ -z \$$1 ]; then
-  $1=$2
-fi
-"
-}
-
-set_default EMACS "$(which emacs)"
-
-echo "*** Emacs version ***"
-echo "EMACS =" $(which $EMACS)
-$EMACS --version
-echo
-
-exec ./run-tests.sh