Update to Spring-Boot 2.5.4 (#94)

* Update versions
* Fix version string
* Adjust pipeline
* Use java 15
* Debug logging for build
* Try with empty headers
* Fix more missing headers
* Different approach to regex matching
* ...
* maan
* Fix test
* Update dependency
* Update js dependencies
* go
* Spring Boot 2.5.2
* Update spring boot
* Try java 16 again
* java 16 still doesn't work

pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.5.1</version>
+        <version>2.5.4</version>
         <relativePath /> <!-- lookup parent from repository -->
     </parent>
 
@@ -38,7 +38,7 @@
         <resilience4j.version>1.7.0</resilience4j.version>
         <guava.version>30.1.1-jre</guava.version>
         <equalsverifier.version>3.1.13</equalsverifier.version>
-        <logstash-encoder.version>6.3</logstash-encoder.version>
+        <logstash-encoder.version>6.6</logstash-encoder.version>
         <!-- https://github.com/skuzzle/cmp/issues/90 Fixes problem with failing contract tests -->
         <json-path.version>2.6.0</json-path.version>