510997: upgrade Guava dependency to version 21

Change-Id: I18129559f9cf702cc124476fd89f0ed4f773cb05
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=510997
diff --git a/org.eclipse.mylyn.context.tasks.tests/META-INF/MANIFEST.MF b/org.eclipse.mylyn.context.tasks.tests/META-INF/MANIFEST.MF
index 867d493..6088bef 100644
--- a/org.eclipse.mylyn.context.tasks.tests/META-INF/MANIFEST.MF
+++ b/org.eclipse.mylyn.context.tasks.tests/META-INF/MANIFEST.MF
@@ -26,6 +26,6 @@
  org.eclipse.mylyn.tests.util,
  org.eclipse.ui.editors,
  org.eclipse.ui.forms,
- com.google.guava;bundle-version="15.0.0"
+ com.google.guava;bundle-version="[21.0.0,22.0.0)"
 Export-Package: org.eclipse.mylyn.context.tasks.tests;x-internal:=true
 Bundle-RequiredExecutionEnvironment: JavaSE-1.8
diff --git a/org.eclipse.mylyn.context.tasks.ui/META-INF/MANIFEST.MF b/org.eclipse.mylyn.context.tasks.ui/META-INF/MANIFEST.MF
index 76023e6..d39d6d7 100644
--- a/org.eclipse.mylyn.context.tasks.ui/META-INF/MANIFEST.MF
+++ b/org.eclipse.mylyn.context.tasks.ui/META-INF/MANIFEST.MF
@@ -19,7 +19,7 @@
  org.eclipse.mylyn.monitor.ui;bundle-version="3.8.0",
  org.eclipse.mylyn.tasks.core;bundle-version="3.8.0",
  org.eclipse.mylyn.tasks.ui;bundle-version="3.8.0",
- com.google.guava;bundle-version="15.0.0"
+ com.google.guava;bundle-version="[21.0.0,22.0.0)"
 Bundle-Vendor: %Bundle-Vendor
 Export-Package: org.eclipse.mylyn.internal.context.tasks.ui;x-internal:=true,
  org.eclipse.mylyn.internal.context.tasks.ui.editors;x-internal:=true