[YUNIKORN-1949] SI: Move to go v1.21 (#105)

Closes: #105

Signed-off-by: Craig Condit <ccondit@apache.org>
diff --git a/.go_version b/.go_version
index 5fb5a6b..d2ab029 100644
--- a/.go_version
+++ b/.go_version
@@ -1 +1 @@
-1.20
+1.21