Add version 7.8 to backport config (elastic#65445)

sorenlouv · web-flow · commit 313d80228acb · 2020-05-06T15:11:29.000+02:00
diff --git a/.backportrc.json b/.backportrc.json
@@ -3,6 +3,7 @@
   "targetBranchChoices": [
     { "name": "master", "checked": true },
     { "name": "7.x", "checked": true },
+    "7.8",
     "7.7",
     "7.6",
     "7.5",
