fix: upgrade org.slf4j:slf4j-api from 1.7.30 to 1.7.31 (#405)

Snyk has created this PR to upgrade org.slf4j:slf4j-api from 1.7.30 to 1.7.31.

See this package in Maven Repository:
https://mvnrepository.com/artifact/org.slf4j/slf4j-api/

See this project in Snyk:
https://app.snyk.io/org/quickfix-j/project/a2ba7698-887e-4fdb-b1ae-1da9d52abae3?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot

pom.xml

@@ -69,9 +69,9 @@
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 		<jdkLevel>1.8</jdkLevel>
-		<slf4j.version>1.7.30</slf4j.version>
+		<slf4j.version>1.7.31</slf4j.version>
 		<junit.version>4.13.1</junit.version>
-		<mainClass />
+		<mainClass/>
 
 		<maven-resources-plugin-version>3.1.0</maven-resources-plugin-version>
 		<maven-compiler-plugin-version>3.8.0</maven-compiler-plugin-version>
@@ -248,7 +248,7 @@
 				        <artifactId>maven-bundle-plugin</artifactId>
                         <executions>
                             <execution>
-                                <phase />
+                                <phase/>
                             </execution>
                         </executions>
 			        </plugin>