Increase memory for SBT in Travis build file

Exception in thread "XMLEventReader" java.lang.OutOfMemoryError: Java heap space
	at java.util.Arrays.copyOf(Arrays.java:3332)
	at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:137)
	at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:121)
	at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:622)
	at java.lang.StringBuilder.append(StringBuilder.java:202)
	at scala.collection.mutable.StringBuilder.append(StringBuilder.scala:267)
	at scala.xml.parsing.MarkupParserCommon.xTakeUntil(MarkupParserCommon.scala:253)
	at scala.xml.parsing.MarkupParser.xCharData(MarkupParser.scala:379)
	at scala.xml.parsing.MarkupParser.content1(MarkupParser.scala:424)
	at scala.xml.parsing.MarkupParser.content(MarkupParser.scala:459)
	at scala.xml.parsing.MarkupParser.element1(MarkupParser.scala:588)
	at scala.xml.parsing.MarkupParser.content1(MarkupParser.scala:433)
	at scala.xml.parsing.MarkupParser.document(MarkupParser.scala:247)
	at scala.xml.pull.XMLEventReader$Parser.$anonfun$run$1(XMLEventReader.scala:96)
	at scala.xml.pull.XMLEventReader$Parser$$Lambda$2957/1828367442.apply(Unknown Source)
	at scala.xml.pull.ProducerConsumerIterator.interruptibly(XMLEventReader.scala:125)
	at scala.xml.pull.XMLEventReader$Parser.run(XMLEventReader.scala:96)
	at java.lang.Thread.run(Thread.java:745)

Author: ashawley

admin/build.sh

@@ -22,4 +22,4 @@ if [[ "$TRAVIS_TAG" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(-[A-Za-z0-9-]+)? ]]; then
   openssl aes-256-cbc -K $K -iv $IV -in admin/secring.asc.enc -out admin/secring.asc -d
 fi
 
-sbt "$publishVersion" clean update +test +publishLocal $extraTarget
+sbt -mem 128 "$publishVersion" clean update +test +publishLocal $extraTarget