Bump 7.2 container to RC1

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

.drone.yml

@@ -171,7 +171,7 @@ pipeline:
         DB: NODB
         PHP: 7.1
   nodb-php7.2:
-    image: nextcloudci/php7.2:php7.2-7
+    image: nextcloudci/php7.2:php7.2-8
     commands:
       - NOCOVERAGE=true TEST_SELECTION=NODB ./autotest.sh sqlite
     when:
@@ -203,7 +203,7 @@ pipeline:
         DB: sqlite
         PHP: 7.1
   sqlite-php7.2:
-    image: nextcloudci/php7.2:php7.2-7
+    image: nextcloudci/php7.2:php7.2-8
     commands:
       - NOCOVERAGE=true TEST_SELECTION=DB ./autotest.sh sqlite
     when: