Adapt linux build now depending on libssl-dev (#45)

native-tls transitive dependency introduced in !41
was added which requires libssl-dev package
installed for the build to find ssl components

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

Remove tag requirement on build jobs,
in order to check that the target still builds

.gitlab-ci.yml

@@ -7,7 +7,7 @@ stages:
 
 build_linux:
   stage: build
-  image: rust:slim-buster
+  image: rust:buster
   script:
      # Build the project for Linux
     - cargo build --release
@@ -25,8 +25,6 @@ build_linux:
     paths:
       - target/release
       - target/debian
-  only:
-    - tags
 
 build_macos:
   stage: build
@@ -56,8 +54,6 @@ build_macos:
     key: "$CI_JOB_NAME-$CI_COMMIT_REF_SLUG"
     paths:
       - target/macos
-  only:
-    - tags
 
 release:
   stage: release