fix: use full path to `cat` in entrypoints

Change-Id: Ice6d621d895804171b9f2aa11fea8dddc3700e26
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/cloudbees-amd64-jenkins-jobs/Dockerfile b/cloudbees-amd64-jenkins-jobs/Dockerfile
index 3d98e56..753ccee 100644
--- a/cloudbees-amd64-jenkins-jobs/Dockerfile
+++ b/cloudbees-amd64-jenkins-jobs/Dockerfile
@@ -12,4 +12,4 @@
     uv pip install --requirements "/tmp/requirements.txt"
 EOF
 
-CMD ["cat"]
+ENTRYPOINT ["/bin/cat"]
diff --git a/cloudbees-amd64-uv/Dockerfile b/cloudbees-amd64-uv/Dockerfile
index 1d9a010..0f843cf 100644
--- a/cloudbees-amd64-uv/Dockerfile
+++ b/cloudbees-amd64-uv/Dockerfile
@@ -13,4 +13,4 @@
 VOLUME /home/jenkins/.jenkins
 VOLUME /home/jenkins/agent
 
-ENTRYPOINT ["cat"]
+ENTRYPOINT ["/bin/cat"]