Use final release URL of Eclipse Platform

This change also updates the URL of the rap-extra-repo.url p2 repository
because the old location is not reachable any more.

Change-Id: If9bae05666fe2af3e43174fbd07ee96efdb3f418
Signed-off-by: Markus Knauer <mknauer@eclipsesource.com>

releng/org.eclipse.rap.build/pom.xml

diff --git a/releng/org.eclipse.rap.build/pom.xml b/releng/org.eclipse.rap.build/pom.xml
index faf9aa7..ab68a94 100644
--- a/releng/org.eclipse.rap.build/pom.xml
+++ b/releng/org.eclipse.rap.build/pom.xml
@@ -29,8 +29,8 @@
      -->
     <jetty-repo.url>https://download.eclipse.org/jetty/updates/jetty-bundles-9.x/9.4.35.v20201120/</jetty-repo.url>
     <orbit-repo.url>https://download.eclipse.org/tools/orbit/downloads/2020-12/</orbit-repo.url>
-    <platform-repo.url>https://download.eclipse.org/eclipse/updates/4.18milestones/S-4.18RC2-202012021800/</platform-repo.url>
-    <rap-extra-repo.url>https://build.eclipse.org/rt/rap/base-platforms/3.14/extra-dependencies/</rap-extra-repo.url>
+    <platform-repo.url>https://download.eclipse.org/eclipse/updates/4.18/R-4.18-202012021800/</platform-repo.url>
+    <rap-extra-repo.url>https://download.eclipse.org/rt/rap/base-platforms/3.14/extra-dependencies/</rap-extra-repo.url>
     <license-repo.url>https://download.eclipse.org/cbi/updates/license/</license-repo.url>
     <!-- The build type, N for nighty builds, S for stable builds. S-builds will be signed. -->
     <buildType>N</buildType>