build/ci: add github actions runner dependencies

Change-Id: I7674796d6280fb838d382ef50296f04932d80e0b
Reviewed-on: https://review.monogon.dev/c/monogon/+/812
Tested-by: Jenkins CI
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/build/ci/Dockerfile b/build/ci/Dockerfile
index f2aef95..aa79dc7 100644
--- a/build/ci/Dockerfile
+++ b/build/ci/Dockerfile
@@ -33,11 +33,13 @@
 	python-unversioned-command \
 	openssl-devel \
 	java-11-openjdk-headless \
+	dotnet-runtime-5.0 \
+	jq \
 	tini
 
 
 # (java-11-openjdk-headless and tini are required for the Jenkins CI agent)
-
+# (dotnet-runtime-5.0 and jq are required for the GitHub Actions runner)
 
 # Create CI build user. This is not used by scripts/bin/bazel, but instead only
 # used by CI infrastructure to run build agents as.