Add a scheduled run for hermes.

.github/workflows/e2e.yaml

@@ -1,5 +1,14 @@
+# The Tests / E2E workflow is used to run end-to-end tests on pull requests originating
+# from the ibc-go repository. The workflow is triggered on a PR opening, when new commits
+# are pushed to the PR, or when the PR is marked ready for review.
+#
+# A scheduled job is also set up to run every night. This job is used to run e2e tests
+# using the hermes relayer.
 name: Tests / E2E
 on:
+  # This schedule is used solely for hermes and is set to run every night.
+  schedule:
+    - cron: "0 0 * * *"
   workflow_dispatch:
   pull_request:
     types:
@@ -37,7 +46,16 @@ jobs:
             echo "Using tag $tag"
             echo "simd-tag=$tag" >> $GITHUB_OUTPUT
           fi
-
+      # get-relayer will return either hermes or rly depending on whether the workflow was triggered
+      # by a scheduled run or not.
+      - id: get-relayer
+        run: |
+          if [ "${{ github.event_name }}" == "schedule" ]
+          then
+            echo "relayer=hermes" >> $GITHUB_OUTPUT
+          else
+            echo "relayer=rly" >> $GITHUB_OUTPUT
+          fi
   # build-e2e ensures that all test code compiles.
   build-e2e:
     if: ${{ !github.event.pull_request.draft && !github.event.pull_request.head.repo.fork && github.actor != 'dependabot[bot]' }}
@@ -80,3 +98,4 @@ jobs:
       chain-binary: 'simd'
       # on regular PRs we won't run interchain account or upgrade tests.
       test-exclusions: 'TestInterTxTestSuite,TestIncentivizedInterTxTestSuite,TestUpgradeTestSuite'
+      relayer-tag: "${{ needs.determine-image-tag.outputs.relayer }}"