Use pinned version of mac image (#367)

Author: florence-rolland

.yamato/sonar.yml

@@ -2,7 +2,7 @@ csharp:
     name: Sonarqube C# Scan
     agent:
         type: Unity::metal::macmini
-        image: package-ci/mac
+        image: package-ci/mac:v1.8.1-822785
         flavor: m1.mac
     variables:
         PROJECT_PATH: tutorials/pick_and_place/PickAndPlaceProject
@@ -36,7 +36,7 @@ standard:
     name: Sonarqube Standard Scan
     agent:
         type: Unity::metal::macmini
-        image: package-ci/mac
+        image: package-ci/mac:v1.8.1-822785
         flavor: m1.mac
     variables:
         SONARQUBE_PROJECT_KEY: ai-robotics-hub-standard
@@ -49,4 +49,4 @@ standard:
         expression: |
             ((pull_request.target eq "main" OR pull_request.target eq "dev")
             AND NOT pull_request.push.changes.all match "**/*.md") OR
-            (push.branch eq "main" OR push.branch eq "dev")
+            (push.branch eq "main" OR push.branch eq "dev")