Allow Spring Security Customizer static imports

Add an additional exclusion to `SpringAvoidStaticImportCheck` so that
the `org.springframework.security.config.Customizer` class can be used.

Closes gh-206

Author: philwebb

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/main/java/io/spring/javaformat/checkstyle/check/SpringAvoidStaticImportCheck.java

@@ -66,6 +66,7 @@ public class SpringAvoidStaticImportCheck extends AvoidStaticImportCheck {
 		excludes.add("org.springframework.restdocs.restassured3.RestAssuredRestDocumentation.*");
 		excludes.add("org.springframework.restdocs.snippet.Attributes.*");
 		excludes.add("org.springframework.restdocs.webtestclient.WebTestClientRestDocumentation.*");
+		excludes.add("org.springframework.security.config.Customizer.*");
 		excludes.add("org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestBuilders.*");
 		excludes.add("org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.*");
 		excludes.add("org.springframework.security.test.web.servlet.setup.SecurityMockMvcConfigurers.*");