Fix go version

Author: Gogen120

go.mod

@@ -1,6 +1,6 @@
 module github.com/selectel/dbaas-go
 
-go 1.21
+go 1.20
 
 require (
 	github.com/gophercloud/gophercloud v1.0.0

go.sum

@@ -6,7 +6,6 @@ github.com/gophercloud/gophercloud v1.0.0/go.mod h1:Q8fZtyi5zZxPS/j9aj3sSxtvj41A
 github.com/jarcoal/httpmock v1.2.0 h1:gSvTxxFR/MEMfsGrvRbdfpRUMBStovlSRLw0Ep1bwwc=
 github.com/jarcoal/httpmock v1.2.0/go.mod h1:oCoTsnAz4+UoOUIf5lJOWV2QQIW5UoeUI6aM2YnWAZk=
 github.com/maxatome/go-testdeep v1.11.0 h1:Tgh5efyCYyJFGUYiT0qxBSIDeXw0F5zSoatlou685kk=
-github.com/maxatome/go-testdeep v1.11.0/go.mod h1:011SgQ6efzZYAen6fDn4BqQ+lUR72ysdyKe7Dyogw70=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=