Adapt linux build now depending on libssl-dev. Introduce tests job (#45, #46)

native-tls transitive dependency introduced in !41 (merged) depends on libssl-dev package installed for the build to find SSL components.

Switching to "non-slim" Debian image which comes with libssl-dev pre-installed.

Introduce tests job.

Close #45 (closed), #46 (closed) .

.gitlab-ci.yml

@@ -2,12 +2,19 @@
 # https://hub.docker.com/r/library/rust/tags/
 
 stages:
+  - tests
   - build
   - release
 
+tests_linux:
+  stage: tests
+  image: rust:buster
+  script:
+    - cargo test
+
 build_linux:
   stage: build
-  image: rust:slim-buster
+  image: rust:buster
   script:
      # Build the project for Linux
     - cargo build --release