[Feature:Autograding] Fixed typo in metadata.json (#35)

Co-authored-by: Stacy Patterson <sep@baker-61.dynamic.rpi.edu>
Co-authored-by: Barb Cutler <bmcutler@users.noreply.github.com>

Author: 3 people

dockerfiles/csci4510/metadata.json

@@ -1,4 +1,4 @@
 {
-    "pushLatest": true
+    "pushLatest": true,
     "latestTag": "spring26"
 }