ci: require gcovr 5.1 for code coverage reports

Stop passing `-j`, it wasn't very useful and it's broken in gcovr 5.1

Change-Id: I17ffb97c2dc9cd8db7c900fbbd4ab5f8f92184dd
diff --git a/.jenkins.d/00-deps.sh b/.jenkins.d/00-deps.sh
index 8ac6896..9593baa 100755
--- a/.jenkins.d/00-deps.sh
+++ b/.jenkins.d/00-deps.sh
@@ -36,7 +36,7 @@
     case $JOB_NAME in
         *code-coverage)
             sudo apt-get -qy install lcov python3-pip
-            pip3 install --user --upgrade --upgrade-strategy=eager 'gcovr~=5.0'
+            pip3 install --user --upgrade --upgrade-strategy=eager 'gcovr~=5.1'
             ;;
         *Docs)
             sudo apt-get -qy install doxygen graphviz python3-pip