chore: update to use go1.21

Signed-off-by: Rui Chen <rui@chenrui.dev>

.github/workflows/windows-validation.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       matrix:
         cache: [false, true]
-        go: [1.20.1]
+        go: [1.21.0]
     steps:
       - uses: actions/checkout@v3
 
@@ -61,7 +61,7 @@ jobs:
             echo 'which go should return "/c/hostedtoolcache/windows/go/${{ matrix.go }}/x64/bin/go"'
             exit 1
           fi
-          if [ $(go env GOROOT) != 'C:\hostedtoolcache\windows\go\${{ matrix.go }}\x64' ];then 
+          if [ $(go env GOROOT) != 'C:\hostedtoolcache\windows\go\${{ matrix.go }}\x64' ];then
             echo 'go env GOROOT should return "C:\hostedtoolcache\windows\go\${{ matrix.go }}\x64"'
             exit 1
           fi

README.md

@@ -61,10 +61,10 @@ steps:
 > **Note**: Due to the peculiarities of YAML parsing, it is recommended to wrap the version in single quotation marks:
 > 
 > ```yaml
->   go-version: '1.20'
+>   go-version: '1.21'
 >  ```
 >  
-> The recommendation is based on the YAML parser's behavior, which interprets non-wrapped values as numbers and, in the case of version 1.20, trims it down to 1.2, which may not be very obvious.
+> The recommendation is based on the YAML parser's behavior, which interprets non-wrapped values as numbers and, in the case of version 1.21, trims it down to 1.2, which may not be very obvious.
 Matching an unstable pre-release:
 
 ```yaml