Revert "Upgrade to Tomcat 8.0.35"

This reverts commit 66e093ed0d. There's
a regression [1] in Tomcat 8.0.35 that causes it to throw an NPE when
it scans a jar file without a manifest. It's already been fixed [2].

See gh-6087

[1] https://svn.apache.org/viewvc/tomcat/tc8.0.x/trunk/java/org/apache/tomcat/util/scan/StandardJarScanner.java?annotate=1742274#l369
[2] https://svn.apache.org/viewvc/tomcat/tc8.0.x/trunk/java/org/apache/tomcat/util/scan/StandardJarScanner.java?annotate=1744197#l369

spring-boot-dependencies/pom.xml

@@ -156,7 +156,7 @@
 		<thymeleaf-extras-conditionalcomments.version>2.1.1.RELEASE</thymeleaf-extras-conditionalcomments.version>
 		<thymeleaf-layout-dialect.version>1.3.3</thymeleaf-layout-dialect.version>
 		<thymeleaf-extras-data-attribute.version>1.3</thymeleaf-extras-data-attribute.version>
-		<tomcat.version>8.0.35</tomcat.version>
+		<tomcat.version>8.0.33</tomcat.version>
 		<undertow.version>1.3.22.Final</undertow.version>
 		<velocity.version>1.7</velocity.version>
 		<velocity-tools.version>2.0</velocity-tools.version>