Use github actions CI

.github/workflows/ci.yml

+name: Continuous integration
+
+on: 
+  pull_request:
+    paths:
+      - "**.wdl"  # Workflow files and task 
+      - "**.yml"  # Ci configuration, tests and docker images 
+      - "!docs/**"
+
+defaults:
+  run:
+    # This is needed for miniconda, see:
+    # https://github.com/marketplace/actions/setup-miniconda#important
+    shell: bash -l {0}  
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    name: Womtool validate and submodule up to date.
+    steps:
+      - uses: actions/checkout@v2.3.4
+        with:
+          submodules: recursive
+      - name: install miniconda
+        uses: conda-incubator/setup-miniconda@v2.0.1
+        with:
+          channels: conda-forge,bioconda,defaults
+        # Conda-incubator uses 'test' environment by default.
+      - name: install requirements
+        run: conda install -n test cromwell miniwdl wdl-aid
+      - name: run linting
+        run: bash scripts/biowdl_lint.sh
\ No newline at end of file

.travis.yml

-# We use conda to install cromwell.
-
-language: python
-
-python:
-  - 3.6
-
-before_install:
-  # Install conda
-  - export MINICONDA=${HOME}/miniconda
-  - export PATH=${MINICONDA}/bin:${PATH}
-  - wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh
-  - bash miniconda.sh -b -f -p ${MINICONDA}
-  - conda config --set always_yes yes
-  - conda config --add channels defaults
-  - conda config --add channels bioconda
-  - conda config --add channels conda-forge
-
-install:
-  - conda install --file requirements-test.txt
-
-script:
-  - bash scripts/biowdl_lint.sh

requirements-test.txt

-# These are the programs used for testing these biowdl tasks.
-# These requirements can be installed with conda with the bioconda channel
-# activated.
-# For more information on how to set up conda with bioconda channel see:
-# http://bioconda.github.io/#install-conda
-# This file can be installed with "conda install --file requirements-test.txt".
-
-cromwell
-womtool
-miniwdl
-wdl-aid