Disable resource chain cache when DevTools is enabled

If the resource chain is used, such as by using the
`"spring.resources.chain.strategy.content.enabled"` property,
resource chain caching can prevent the developer from seeing
changes made to resources, so that caching should be disabled
when DevTools is enabled.

This commit sets the `"spring.resources.chain.cache"` property
to `true` when devtools is enabled.

Author: candrews

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/env/DevToolsPropertyDefaultsPostProcessor.java

@@ -54,6 +54,7 @@ public class DevToolsPropertyDefaultsPostProcessor implements EnvironmentPostPro
 		properties.put("server.session.persistent", "true");
 		properties.put("spring.h2.console.enabled", "true");
 		properties.put("spring.resources.cache-period", "0");
+		properties.put("spring.resources.chain.cache", "false");
 		properties.put("spring.template.provider.cache", "false");
 		properties.put("spring.mvc.log-resolved-exception", "true");
 		PROPERTIES = Collections.unmodifiableMap(properties);