Update minimum server version to 10.7.0 (#947)

Author: marianunez

plugin.json

@@ -5,7 +5,7 @@
     "homepage_url": "https://github.com/mattermost/mattermost-plugin-github",
     "support_url": "https://github.com/mattermost/mattermost-plugin-github/issues",
     "icon_path": "assets/icon.svg",
-    "min_server_version": "7.1.0",
+    "min_server_version": "10.7.0",
     "server": {
       "executables": {
           "linux-amd64": "server/dist/plugin-linux-amd64",