Update dependency com.fasterxml.jackson.core:jackson-databind to version 2.9.4

[javier-godoy]

Known high severity security vulnerabilities (CVE-2017-15095, CVE-2017-17485, CVE-2018-5968) detected in com.fasterxml.jackson.core:jackson-databind >= 2.9.0, < 2.9.4 defined in pom.xml.

pom.xml update suggested: com.fasterxml.jackson.core:jackson-databind ~> 2.9.4.

[javier-godoy]

Fixed.