Bump version to 2.15.0 and tidy release notes

PiperOrigin-RevId: 389871495

constants.gradle

@@ -13,8 +13,8 @@
 // limitations under the License.
 project.ext {
     // ExoPlayer version and version code.
-    releaseVersion = '2.14.2'
-    releaseVersionCode = 2014002
+    releaseVersion = '2.15.0'
+    releaseVersionCode = 2015000
     minSdkVersion = 16
     appTargetSdkVersion = 29
     targetSdkVersion = 30

library/common/src/main/java/com/google/android/exoplayer2/ExoPlayerLibraryInfo.java

@@ -26,11 +26,11 @@ public final class ExoPlayerLibraryInfo {
 
   /** The version of the library expressed as a string, for example "1.2.3". */
   // Intentionally hardcoded. Do not derive from other constants (e.g. VERSION_INT) or vice versa.
-  public static final String VERSION = "2.14.2";
+  public static final String VERSION = "2.15.0";
 
   /** The version of the library expressed as {@code "ExoPlayerLib/" + VERSION}. */
   // Intentionally hardcoded. Do not derive from other constants (e.g. VERSION) or vice versa.
-  public static final String VERSION_SLASHY = "ExoPlayerLib/2.14.2";
+  public static final String VERSION_SLASHY = "ExoPlayerLib/2.15.0";
 
   /**
    * The version of the library expressed as an integer, for example 1002003.
@@ -40,7 +40,7 @@ public final class ExoPlayerLibraryInfo {
    * integer version 123045006 (123-045-006).
    */
   // Intentionally hardcoded. Do not derive from other constants (e.g. VERSION) or vice versa.
-  public static final int VERSION_INT = 2014002;
+  public static final int VERSION_INT = 2015000;
 
   /**
    * The default user agent for requests made by the library.