Update dependency go to v1.26.4

Author: renovate-bot

.github/workflows/integration-tests-against-omni.yaml

@@ -154,7 +154,7 @@ jobs:
 
       - uses: actions/setup-go@v2
         with:
-          go-version: "1.25.11"
+          go-version: "1.26.4"
       - run: go version
       - run: go build
       - name: Wait for Spanner Omni to start

.github/workflows/lint.yaml

@@ -26,7 +26,7 @@ jobs:
       - uses: actions/setup-go@v2
         with:
           # Need to use a version less than 1.25 due to https://github.com/golang/go/issues/74462.
-          go-version: '>=1.23.0 <1.25.9'
+          go-version: '<1.26.5'
       - uses: actions/setup-node@v2
         with:
           node-version: 18

.github/workflows/test-coverage.yaml

@@ -25,7 +25,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v2
         with:
-          go-version: "1.25.11"
+          go-version: "1.26.4"
       - name: Set up Node.js
         uses: actions/setup-node@v2
         with: