Updated go versions used in workflows to 1.21 (#6260)

* Updated go versions used in workflows to 1.21

Signed-off-by: Neo2308 <pradha.krishna.cse17@itbhu.ac.in>
Co-authored-by: RadhaKrishna <radha.peteti@appdynamics.com>

.github/workflows/go.coverage.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: '~1.20.0'
+          go-version: '~1.21.0'
         id: go
 
       - name: Build

.github/workflows/go.test.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: '~1.20.0'
+          go-version: '~1.21.0'
         id: go
 
       - name: Build
@@ -36,7 +36,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: '~1.20.0'
+          go-version: '~1.21.0'
         id: go
 
       - name: Build
@@ -55,7 +55,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: '~1.20.0'
+          go-version: '~1.21.0'
         id: go
 
       - name: Build

.github/workflows/golangci-lint.yml

@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '~1.20.0'
+          go-version: '~1.21.0'
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3.6.0
         with:

.github/workflows/make.doc.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v4
         with:
-          go-version: '~1.20.0'
+          go-version: '~1.21.0'
 
       - name: Update Docs
         run: |

README.md

@@ -74,7 +74,7 @@ CoreDNS requires Go to compile. However, if you already have docker installed an
 setup a Go environment, you could build CoreDNS easily:
 
 ```
-$ docker run --rm -i -t -v $PWD:/v -w /v golang:1.20 make
+$ docker run --rm -i -t -v $PWD:/v -w /v golang:1.21 make
 ```
 
 The above command alone will have `coredns` binary generated.