Update build configuration for RAP Tools 3.18.0 RC2

- Use Eclipse Platform 4.21 I20210906-0500 (RC2a)

Change-Id: If4b6994ebeca0c8202f0c5b0791f03516dd5b01b
Signed-off-by: Markus Knauer <mknauer@eclipsesource.com>
diff --git a/features/org.eclipse.rap.tools.feature/.forceQualifierUpdate b/features/org.eclipse.rap.tools.feature/.forceQualifierUpdate
index 90154f0..4de5ea3 100644
--- a/features/org.eclipse.rap.tools.feature/.forceQualifierUpdate
+++ b/features/org.eclipse.rap.tools.feature/.forceQualifierUpdate
@@ -1 +1 @@
-2021-09-01T12:00:00+00:00
+2021-09-08T12:00:00+00:00
diff --git a/releng/org.eclipse.rap.tools.build/target.definition/org.eclipse.rap.tools.target.definition.target b/releng/org.eclipse.rap.tools.build/target.definition/org.eclipse.rap.tools.target.definition.target
index 5a98e6a..3623125 100644
--- a/releng/org.eclipse.rap.tools.build/target.definition/org.eclipse.rap.tools.target.definition.target
+++ b/releng/org.eclipse.rap.tools.build/target.definition/org.eclipse.rap.tools.target.definition.target
@@ -7,9 +7,9 @@
 			<unit id="org.eclipse.license.feature.group" version="2.0.2.v20181016-2210"/>
 		</location>
 		<location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="slicer" includeSource="true" type="InstallableUnit">
-			<repository location="https://download.eclipse.org/eclipse/updates/4.21-I-builds/I20210830-0600/"/>
+			<repository location="https://download.eclipse.org/eclipse/updates/4.21-I-builds/I20210906-0500/"/>
 			<unit id="org.eclipse.core.runtime.feature.feature.group" version="1.2.1400.v20210823-1805"/>
-			<unit id="org.eclipse.e4.rcp.feature.group" version="4.21.0.v20210828-0802"/>
+			<unit id="org.eclipse.e4.rcp.feature.group" version="4.21.0.v20210906-0842"/>
 			<unit id="org.eclipse.ecf.core.feature.feature.group" version="1.5.702.v20210409-2301"/>
 			<unit id="org.eclipse.ecf.core.ssl.feature.feature.group" version="1.1.501.v20210409-2301"/>
 			<unit id="org.eclipse.ecf.filetransfer.feature.feature.group" version="3.14.1800.v20210618-0642"/>
@@ -20,13 +20,13 @@
 			<unit id="org.eclipse.equinox.compendium.sdk.feature.group" version="3.22.100.v20210726-0943"/>
 			<unit id="org.eclipse.equinox.core.feature.feature.group" version="1.13.300.v20210823-1805"/>
 			<unit id="org.eclipse.equinox.core.sdk.feature.group" version="3.23.100.v20210823-1805"/>
-			<unit id="org.eclipse.jdt.feature.group" version="3.18.900.v20210830-0600"/>
-			<unit id="org.eclipse.jdt.source.feature.group" version="3.18.900.v20210830-0600"/>
-			<unit id="org.eclipse.pde.feature.group" version="3.14.900.v20210830-0600"/>
-			<unit id="org.eclipse.pde.source.feature.group" version="3.14.900.v20210830-0600"/>
-			<unit id="org.eclipse.platform.feature.group" version="4.21.0.v20210830-0942"/>
-			<unit id="org.eclipse.platform.source.feature.group" version="4.21.0.v20210830-0942"/>
-			<unit id="org.eclipse.rcp.feature.group" version="4.21.0.v20210830-0942"/>
+			<unit id="org.eclipse.jdt.feature.group" version="3.18.900.v20210906-0500"/>
+			<unit id="org.eclipse.jdt.source.feature.group" version="3.18.900.v20210906-0500"/>
+			<unit id="org.eclipse.pde.feature.group" version="3.14.900.v20210906-0500"/>
+			<unit id="org.eclipse.pde.source.feature.group" version="3.14.900.v20210906-0500"/>
+			<unit id="org.eclipse.platform.feature.group" version="4.21.0.v20210906-0842"/>
+			<unit id="org.eclipse.platform.source.feature.group" version="4.21.0.v20210906-0842"/>
+			<unit id="org.eclipse.rcp.feature.group" version="4.21.0.v20210906-0842"/>
 		</location>
 		<location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="slicer" includeSource="true" type="InstallableUnit">
 			<repository location="https://download.eclipse.org/webtools/jetty/10.0.6/repository/"/>