fix misleading timestamp value from tests and lint issues

Removes timestamp with single digit hour code to avoid confusion. Also
fixes lint issues.

References:
* golang/go#57912 (comment)
* GOSDK-2932

Author: aajtodd

config/shared_test.go

@@ -14,7 +14,7 @@ const ecsResponse = `{
   "SecretAccessKey": "ecs-secret-key",
   "Token": "token",
   "Expiration": "2100-01-01T00:00:00Z",
-  "LastUpdated": "2009-11-23T0:00:00Z"
+  "LastUpdated": "2009-11-23T00:00:00Z"
 }`
 
 const ec2MetadataResponse = `{
@@ -24,7 +24,7 @@ const ec2MetadataResponse = `{
   "SecretAccessKey": "ec2-secret-key",
   "Token": "token",
   "Expiration": "2100-01-01T00:00:00Z",
-  "LastUpdated": "2009-11-23T0:00:00Z"
+  "LastUpdated": "2009-11-23T00:00:00Z"
 }`
 
 const assumeRoleRespMsg = `

credentials/ec2rolecreds/provider_test.go

@@ -28,13 +28,13 @@ const credsRespTmpl = `{
   "SecretAccessKey" : "secret",
   "Token" : "token",
   "Expiration" : "%s",
-  "LastUpdated" : "2009-11-23T0:00:00Z"
+  "LastUpdated" : "2009-11-23T00:00:00Z"
 }`
 
 const credsFailRespTmpl = `{
   "Code": "ErrorCode",
   "Message": "ErrorMsg",
-  "LastUpdated": "2009-11-23T0:00:00Z"
+  "LastUpdated": "2009-11-23T00:00:00Z"
 }`
 
 type mockClient struct {