chore: update version and nightly CI for 1.17 (#19208)

Update version file to 1.18-dev, and replace 1.13 nightly test with
1.17.

.github/workflows/nightly-test-1.17.x.yaml

@@ -1,7 +1,7 @@
 # Copyright (c) HashiCorp, Inc.
 # SPDX-License-Identifier: MPL-2.0
 
-name: Nightly Frontend Test 1.13.x
+name: Nightly Frontend Test 1.17.x
 on:
   schedule:
     - cron: '0 4 * * *'
@@ -9,8 +9,8 @@ on:
 
 env:
   EMBER_PARTITION_TOTAL: 4        # Has to be changed in tandem with the matrix.partition
-  BRANCH: "release/1.13.x"
+  BRANCH: "release/1.17.x"
-  BRANCH_NAME: "release-1.13.x"   # Used for naming artifacts
+  BRANCH_NAME: "release-1.17.x"   # Used for naming artifacts
   GOPRIVATE: github.com/hashicorp # Required for enterprise deps
 
 jobs:

version/VERSION

@@ -1 +1 @@
-1.17.0-dev
+1.18.0-dev