Update golang in build script (#4504)

Update build.sh golang version

---

#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [x] 💪 Manual
- [ ] ⚡ Unit test
- [ ] 💚 E2E

build/build.sh

@@ -12,7 +12,7 @@ usage() {
 }
 
 ROOT=$(dirname $(dirname $(readlink -f $0)))
-GOVER=1.19                           # go version
+GOVER=1.21                           # go version
 CORSO_BUILD_CACHE="/tmp/.corsobuild" # shared persistent cache
 
 # Figure out os and architecture