Add Docker image for running GitHub Actions locally using ACT

ci/act-nextflow-image/Dockerfile

@@ -0,0 +1,5 @@
+# Docker image to be used for running CI locally using ACT
+FROM ghcr.io/catthehacker/ubuntu:act-latest
+
+# Install java
+RUN apt-get update && sudo apt-get install -y openjdk-21-jre

ci/act-nextflow-image/build.sh

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+docker build -t genomicmedicinesweden/act-nextflow:latest .

ci/act-nextflow-image/push.sh

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+docker push genomicmedicinesweden/act-nextflow:latest

scripts/runci.sh

@@ -1,14 +1,16 @@
 #!/bin/bash
 # This script uses the act tool to execute GitHub Actions workflows locally
 # for increased iteration speed.
+# It requires that you have Docker installed.
 # It requires the act [1] binary to be available in your path.
 # It also requires a late version of the GitHub commandline client (`gh`) [2]
 # to be installed and available on your path.
 # [1] https://github.com/nektos/act
 # [2] https://github.com/cli/cli
-act -v \
+# Note: You can add the -v option to get more output, for troubleshooting.
+act \
     -s GITHUB_TOKEN="$(gh auth token)" \
     -e event.json \
-    -P ubuntu-latest=catthehacker/ubuntu:act-latest \
+    -P ubuntu-latest=genomicmedicinesweden/act-nextflow:latest \
     -W .github/workflows/ci.yml \
 |& tee ci-output-$(date +%Y%m%d.%H%M%S).log