go-env: add page (#4003)

Signed-off-by: gonejack <igonejack@gmail.com>

pages/common/go-env.md

@@ -0,0 +1,16 @@
+# go env
+
+> Tool for printing Go environment information.
+> More information: <https://golang.org/cmd/go/>.
+
+- Show all go environment information:
+
+`go env`
+
+- Show specific environment variable:
+
+`go env {{GOPATH}}`
+
+- Set go environment value:
+
+`go env -w {{NAME}}={{VALUE}}`