ISIS-1353: updates slf4j from 1.7.13 to 1.7.21
ISIS-1353: updates slf4j from 1.7.13 to 1.7.21

            <dependency>
              <groupId>org.slf4j</groupId>
              <artifactId>slf4j-api</artifactId>
              <version>${slf4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-log4j12</artifactId>
                <version>${slf4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>jcl-over-slf4j</artifactId>
                <version>${slf4j.version}</version>
            </dependency>

incodehq/isis,incodehq/isis,apache/isis,sanderginn/isis,estatio/isis,niv0/isis,sanderginn/isis,niv0/isis,sanderginn/isis,estatio/isis,apache/isis,apache/isis,niv0/isis,apache/isis,apache/isis,niv0/isis,estatio/isis,incodehq/isis,oscarbou/isis,oscarbou/isis,oscarbou/isis,estatio/isis,apache/isis,incodehq/isis,sanderginn/isis,oscarbou/isis