scripts: Golang version update

Update Go version to 1.21.

Change-Id: I9f118d2b005b21c6b4c4031af2b9aae3b9a6e42d
Signed-off-by: Emilia Haligowska <emilia.haligowska@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/19420


Community-CI: Mellanox Build Bot
Reviewed-by: Pawel Piatek <pawelx.piatek@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Marek Chomnicki <marek.chomnicki@intel.com>
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>