Add XML syntax highlighting in READMEs [skip ci] (#2922)

mbrukman · pongad · commit 45a99780c10e · 2018-02-20T10:48:09.000+11:00
This makes the `pom.xml` code samples more readable.
diff --git a/README.md b/README.md
@@ -275,7 +275,7 @@ Version Management
 
 The easiest way to solve version conflicts is to use google-cloud's BOM. In Maven, add the following to your POM:
 
-```
+```xml
   <dependencyManagement>
     <dependencies>
       <dependency>
diff --git a/google-cloud-bom/README.md b/google-cloud-bom/README.md
@@ -6,7 +6,7 @@ components plus its dependencies.
 
 To use it in Maven, add the following to your POM:
 
-```
+```xml
   <dependencyManagement>
     <dependencies>
       <dependency>
