fix(boot2): Allow paths with URL-encoded slashes (#454)

Spring Boot 2 tightened up restrictions, but CI job names may legitimately include encoded slashes

See spinnaker/spinnaker#4477

igor-web/src/main/groovy/com/netflix/spinnaker/igor/config/IgorConfig.groovy

@@ -37,6 +37,7 @@ import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import org.springframework.core.Ordered
 import org.springframework.http.HttpStatus
+import org.springframework.security.web.firewall.StrictHttpFirewall
 import org.springframework.web.bind.annotation.ControllerAdvice
 import org.springframework.web.bind.annotation.ExceptionHandler
 import org.springframework.web.bind.annotation.ResponseBody
@@ -78,6 +79,13 @@ class IgorConfig extends WebMvcConfigurerAdapter {
         return frb
     }
 
+    @Bean
+    StrictHttpFirewall httpFirewall() {
+      def firewall = new StrictHttpFirewall()
+      firewall.allowUrlEncodedSlash = true
+      return firewall
+    }
+
     @Bean
     BuildServices buildServices() {
         new BuildServices()