CI: image with 20.04 and solved small bug

.gitlab-ci.yml

@@ -66,6 +66,7 @@ stages:
   - if [ -d wolf ]; then
   -   echo "directory wolf exists"
   -   cd wolf
+  -   git checkout devel
   -   git pull
   -   git checkout $WOLF_CORE_BRANCH
   - else
@@ -164,3 +165,24 @@ build_and_test:bionic:
     - ldconfig # update links (shared libraries)
   script:
     - *build_and_test_definition
+
+############ UBUNTU 20.04 TESTS ############
+build_and_test:focal:
+  image: labrobotica/wolf_deps:20.04
+  stage: build_and_test
+  cache:
+    - key: wolf-focal
+      paths:
+      - ci_deps/wolf/
+    - key: gnssutils-focal
+      paths:
+      - ci_deps/gnss_utils/
+  except:
+    - master
+  before_script:
+    - *preliminaries_definition
+    - *install_wolf_definition
+    - *install_gnssutils_definition
+    - ldconfig # update links (shared libraries)
+  script:
+    - *build_and_test_definition