Update repo.zynthbox.io repo name for bullseye

.gitlab-ci.yml

@@ -33,7 +33,7 @@ build-zynthbox-image-armhf:
     # Setup Zynthbox Repo sourceline
     - echo "# Setup Zynthbox Repo sourceline"
     - echo "ZYNTHIANOS_ZYNTHBOX_REPO_KEY_URL='https://repo.zynthbox.io/repo_key.pub'" >> ZynthianOS/src/modules/zynthianos/config
-    - echo "ZYNTHIANOS_ZYNTHBOX_REPO_SOURCELINE='deb http://repo.zynthbox.io/testing buster main'" >> ZynthianOS/src/modules/zynthianos/config
+    - echo "ZYNTHIANOS_ZYNTHBOX_REPO_SOURCELINE='deb http://repo.zynthbox.io/testing-bullseye bullseye main'" >> ZynthianOS/src/modules/zynthianos/config
 
     # Download prebuilt realtime kernel
     - echo "# Download prebuilt realtime kernel"