Update agent version to 1.1 in config.yaml (#4430)

Since 1.1 is released, this change updates the default agent tag in config.yaml to 1.1.

edgelet/contrib/config/linux/config.yaml

@@ -46,7 +46,7 @@ agent:
   type: "docker"
   env: {}
   config:
-    image: "mcr.microsoft.com/azureiotedge-agent:1.0"
+    image: "mcr.microsoft.com/azureiotedge-agent:1.1"
     auth: {}
 
 ###############################################################################

edgelet/contrib/config/linux/debian/config.yaml

@@ -46,7 +46,7 @@ agent:
   type: "docker"
   env: {}
   config:
-    image: "mcr.microsoft.com/azureiotedge-agent:1.0"
+    image: "mcr.microsoft.com/azureiotedge-agent:1.1"
     auth: {}
 
 ###############################################################################

edgelet/edgelet-docker/config/unix/default.yaml

@@ -3,7 +3,7 @@ agent:
   type: "docker"
   env: {}
   config:
-    image: "mcr.microsoft.com/azureiotedge-agent:1.0"
+    image: "mcr.microsoft.com/azureiotedge-agent:1.1"
     auth: {}
 
 hostname: "localhost"