Make digital twins project use ETag consistently rather than Etag

sdk/digitaltwins/azure-digitaltwins-core/src/main/java/com/azure/digitaltwins/core/models/BasicDigitalTwin.java

@@ -60,7 +60,7 @@ public String getId() {
      * Gets a string representing a weak ETag for the entity that this request performs an operation against, as per RFC7232.
      * @return A string representing a weak ETag for the entity that this request performs an operation against, as per RFC7232.
      */
-    public String getEtag() {
+    public String getETag() {
         return twinETag;
     }
 
@@ -69,7 +69,7 @@ public String getEtag() {
      * @param twinETag A string representing a weak ETag for the entity that this request performs an operation against, as per RFC7232.
      * @return The BasicDigitalTwin object itself.
      */
-    public BasicDigitalTwin setEtag(String twinETag) {
+    public BasicDigitalTwin setETag(String twinETag) {
         this.twinETag = twinETag;
         return this;
     }

sdk/digitaltwins/azure-digitaltwins-core/src/samples/java/com/azure/digitaltwins/core/ComponentSyncSamples.java

@@ -122,7 +122,7 @@ public static void runComponentSample() throws JsonProcessingException {
             HashMap component1 = mapper.readValue(component1RawText, HashMap.class);
 
             ConsoleLogger.print("Retrieved digital twin using generic API to use built in deserialization into a BasicDigitalTwin with Id: " + basicDigitalTwin.getId() + ":\n\t"
-                + "Etag: " + basicDigitalTwin.getEtag() + "\n\t"
+                + "ETag: " + basicDigitalTwin.getETag() + "\n\t"
                 + "Prop1: " + basicDigitalTwin.getContents().get("Prop1") + "\n\t"
                 + "Prop2: " + basicDigitalTwin.getContents().get("Prop2") + "\n\t"
                 + "ComponentProp1: " + component1.get("ComponentProp1") + "\n\t"

sdk/digitaltwins/azure-digitaltwins-core/src/samples/java/com/azure/digitaltwins/core/serialization/CustomDigitalTwin.java

@@ -35,11 +35,11 @@ public CustomDigitalTwin setId(String id) {
         return this;
     }
 
-    public String getEtag() {
+    public String getETag() {
         return etag;
     }
 
-    public CustomDigitalTwin setEtag(String etag) {
+    public CustomDigitalTwin setETag(String etag) {
         this.etag = etag;
         return this;
     }