Remove GOTOOLCHAIN from most GitHub workflows

The "actions/setup-go" action behaves correctly since v6.

Author: cbandy

.github/workflows/codeql-analysis.yaml

@@ -9,11 +9,6 @@ on:
   schedule:
     - cron: '10 18 * * 2'
 
-env:
-  # Use the Go toolchain installed by setup-go
-  # https://github.com/actions/setup-go/issues/457
-  GOTOOLCHAIN: local
-
 jobs:
   analyze:
     if: ${{ github.repository == 'CrunchyData/postgres-operator' }}

.github/workflows/govulncheck.yaml

@@ -10,6 +10,8 @@ on:
 env:
   # Use the Go toolchain installed by setup-go
   # https://github.com/actions/setup-go/issues/457
+  #
+  # TODO(govulncheck): Remove when "golang/govulncheck-action" uses "actions/setup-go" v6 or newer
   GOTOOLCHAIN: local
 
 jobs:

.github/workflows/lint.yaml

@@ -3,11 +3,6 @@ name: Linters
 on:
   pull_request:
 
-env:
-  # Use the Go toolchain installed by setup-go
-  # https://github.com/actions/setup-go/issues/457
-  GOTOOLCHAIN: local
-
 jobs:
   golangci-lint:
     runs-on: ubuntu-24.04

.github/workflows/test.yaml

@@ -6,11 +6,6 @@ on:
     branches:
       - main
 
-env:
-  # Use the Go toolchain installed by setup-go
-  # https://github.com/actions/setup-go/issues/457
-  GOTOOLCHAIN: local
-
 jobs:
   go-test:
     runs-on: ubuntu-24.04

.github/workflows/trivy.yaml

@@ -8,10 +8,6 @@ on:
       - main
 
 env:
-  # Use the Go toolchain installed by setup-go
-  # https://github.com/actions/setup-go/issues/457
-  GOTOOLCHAIN: local
-
   # Use the committed Trivy configuration files.
   TRIVY_IGNOREFILE: .trivyignore.yaml
   TRIVY_SECRET_CONFIG: trivy-secret.yaml