Update basics chapter for knative v0.4.0

The serving 'pinned' keyword is being deprecated, so move over to
using 'release' and  'revisions' for forward compat.

Author: lberk

01-basics/knative/service-pinned-rev1.yaml

@@ -3,8 +3,8 @@ kind: Service
 metadata:
   name: greeter
 spec:
-  pinned:
-    revisionName: greeter-00001
+  release:
+    revisions: ["greeter-00001"]
     configuration:
       revisionTemplate:
         spec:

01-basics/knative/service-pinned-rev2.yaml

@@ -3,8 +3,8 @@ kind: Service
 metadata:
   name: greeter
 spec:
-  pinned:
-    revisionName: greeter-00002
+  release:
+    revisions: ["greeter-00002"]
     configuration:
       revisionTemplate:
         spec:

documentation/modules/ROOT/pages/02-basic-fundas.adoc

@@ -193,16 +193,16 @@ kind: Service
 metadata:
   name: greeter
 spec:
-  pinned: #<1>
-    revisionName: greeter-00001
+  release: #<1>
+    revisions: ["greeter-00001"]
   configuration:
     revisionTemplate:
       spec:
         container:
           image: dev.local/rhdevelopers/greeter:0.0.1
 ----
 
-<1> The **pinned** attribute in service resource file will make Knative use the revision specified in the **revisionName** attribute.
+<1> The **release** attribute in service resource file will make Knative use the revision specified in the **revisions** attribute.
 
 Let redeploy the greeter service to be pinned to revision __greeter-00001__: