Change version requirements to match the manual selection

Author: rdner

.agent-versions.json

@@ -2,8 +2,8 @@
   "testVersions": [
     "8.13.2-SNAPSHOT",
     "8.13.1",
-    "8.12.2",
     "8.12.3-SNAPSHOT",
+    "8.12.2",
     "7.17.20-SNAPSHOT",
     "7.17.19"
   ]

magefile.go

@@ -1606,8 +1606,8 @@ func (Integration) UpdateVersions(ctx context.Context) error {
 
 	reqs := upgradetest.VersionRequirements{
 		UpgradeToVersion: bversion.Agent,
-		CurrentMajors:    2,
-		PreviousMinors:   1,
+		CurrentMajors:    1,
+		PreviousMinors:   2,
 		PreviousMajors:   1,
 		SnapshotBranches: branches,
 	}