ci: Add testing for eopkg backend on Solus container

Note: silkeh is part of the Solus staff and maintains the docker images
for Solus, although, they have not been officalized yet.

Author: joebonrichie

.github/workflows/build-test.yml

@@ -18,6 +18,8 @@ jobs:
             backend: alpm
           - distro: fedora
             backend: zypp
+          - distro: solus
+            backend: eopkg
       fail-fast: false
 
     steps:

tests/ci/Dockerfile-solus

@@ -0,0 +1,13 @@
+FROM silkeh/solus:devel
+
+RUN eopkg -y upgrade
+RUN eopkg -y install \
+    packagekit-devel \
+    sqlite3-devel \
+    vala \
+    gstreamer-1.0-plugins-base-devel \
+    libgtk-3-devel \
+    docbook-xml
+
+RUN mkdir /build
+WORKDIR /build