rcp: Fix 4.20 build after missing c.g.gson version

Fix the recently (yet repeatedly) failing build [1], by adding the now
required com.google.gson to both target files; base this on [2]'s fix.

[1]https://ci.eclipse.org/tracecompass/job/tracecompass-incubator-nightly-2021-06
[2]https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/203585

Change-Id: If873a07bf0877a810c11790b2e17f6c8afcbd470
Signed-off-by: Marco Miller <marco.miller@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass.incubator/org.eclipse.tracecompass.incubator/+/203453
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>

common/org.eclipse.tracecompass.incubator.target/tracecompass-incubator-e4.20.target

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde version="3.8"?>
-<target name="tracecompass-incubator-e4.20" sequenceNumber="7">
+<target name="tracecompass-incubator-e4.20" sequenceNumber="8">
 <locations>
 <location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="planner" includeSource="true" type="InstallableUnit">
 <unit id="org.eclipse.cdt.gnu.dsf.feature.group" version="0.0.0"/>
@@ -35,6 +35,7 @@
 <unit id="com.fasterxml.jackson.datatype.jackson-datatype-guava.source" version="0.0.0"/>
 <unit id="com.fasterxml.jackson.module.jackson-module-jaxb-annotations" version="0.0.0"/>
 <unit id="com.fasterxml.jackson.module.jackson-module-jaxb-annotations.source" version="0.0.0"/>
+<unit id="com.google.gson" version="0.0.0"/>
 <unit id="com.google.guava" version="27.1.0.v20190517-1946"/>
 <unit id="jakarta.xml.bind" version="2.3.3.v20201118-1818"/>
 <unit id="javassist" version="0.0.0"/>

common/org.eclipse.tracecompass.incubator.target/tracecompass-incubator-master.target

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde version="3.8"?>
-<target name="tracecompass-incubator-master" sequenceNumber="71">
+<target name="tracecompass-incubator-master" sequenceNumber="72">
 <locations>
 <location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="planner" includeSource="true" type="InstallableUnit">
 <unit id="org.eclipse.cdt.gnu.dsf.feature.group" version="0.0.0"/>
@@ -61,6 +61,7 @@
 <unit id="org.glassfish.jersey.containers.servlet.core.source" version="0.0.0"/>
 <unit id="org.glassfish.jersey.ext.entityfiltering" version="0.0.0"/>
 <unit id="org.glassfish.jersey.ext.entityfiltering.source" version="0.0.0"/>
+<unit id="com.google.gson" version="0.0.0"/>
 <unit id="com.google.guava" version="30.1.0.v20221112-0806"/>
 <unit id="jakarta.xml.bind" version="2.3.3.v20221203-1659"/>
 <unit id="org.antlr.runtime" version="3.2.0.v20220404-1927"/>