[YUNIKORN-1694] Bump go version in go.mod to 1.20 (#91)

Closes: #91

Signed-off-by: Craig Condit <ccondit@apache.org>
diff --git a/go.mod b/go.mod
index bc2f719..f26dfcc 100644
--- a/go.mod
+++ b/go.mod
@@ -19,7 +19,7 @@
 
 module github.com/apache/yunikorn-scheduler-interface
 
-go 1.15
+go 1.20
 
 require (
 	github.com/golang/protobuf v1.2.0
@@ -28,6 +28,12 @@
 	google.golang.org/protobuf v1.26.0-rc.1
 )
 
+require (
+	golang.org/x/sys v0.6.0 // indirect
+	golang.org/x/text v0.8.0 // indirect
+	google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8 // indirect
+)
+
 replace (
 	github.com/golang/protobuf => github.com/golang/protobuf v1.2.0
 	golang.org/x/crypto => golang.org/x/crypto v0.7.0