chore: update integration test matrix for Kong Gateway OSS and enterprise

This commit also removes the requirement to pull the Kong Gateway nightly
image from an internal repo and utilizes the newly introduced public
repository for nightly images.

Author: mikefero

.github/workflows/codeql-analysis.yml

@@ -40,11 +40,11 @@ jobs:
     steps:
     - name: Checkout repository
       uses: actions/checkout@v3
-      
+
     - name: Setup go
       uses: actions/setup-go@v4
       with:
-        go-version: 1.18
+        go-version: '^1.20'
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/integration-enterprise.yaml

@@ -34,7 +34,7 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v4
         with:
-          go-version: '^1.18'
+          go-version: '^1.20'
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Login to Docker Hub

.github/workflows/integration-konnect.yaml

@@ -14,7 +14,7 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v4
         with:
-          go-version: '^1.18'
+          go-version: '^1.20'
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Run integration tests

.github/workflows/integration.yaml

@@ -34,7 +34,7 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v4
         with:
-          go-version: '^1.18'
+          go-version: '^1.20'
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Setup Kong

.github/workflows/release.yaml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: 1.18
+          go-version: 1.20
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v4
         with:

.github/workflows/test.yaml

@@ -13,7 +13,7 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v4
         with:
-          go-version: '^1.18'
+          go-version: '^1.20'
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Setup golangci-lint

go.mod

@@ -1,6 +1,6 @@
 module github.com/kong/deck
 
-go 1.18
+go 1.20
 
 replace github.com/yudai/gojsondiff v1.0.0 => github.com/Kong/gojsondiff v1.3.0