Add major and minor version numbers to summary files.

pkg/analyzer/lib/src/summary/format.fbs

Index: pkg/analyzer/lib/src/summary/format.fbs
diff --git a/pkg/analyzer/lib/src/summary/format.fbs b/pkg/analyzer/lib/src/summary/format.fbs
index 16a7cfb43f87e4fac3cfb9eb61133a40b3aad924..63828ff05ca60c017d82229956b2a6dbe2466479 100644
--- a/pkg/analyzer/lib/src/summary/format.fbs
+++ b/pkg/analyzer/lib/src/summary/format.fbs
@@ -809,6 +809,18 @@ table PackageBundle {
   linkedLibraryUris:[string] (id: 1);
 
   /**
+   * Major version of the summary format.  See
+   * [PackageBundleAssembler.currentMajorVersion].
+   */
+  majorVersion:uint (id: 5);
+
+  /**
+   * Minor version of the summary format.  See
+   * [PackageBundleAssembler.currentMinorVersion].
+   */
+  minorVersion:uint (id: 6);
+
+  /**
    * List of MD5 hashes of the files listed in [unlinkedUnitUris].  Each hash
    * is encoded as a hexadecimal string using lower case letters.
    */