Update dependency org.testcontainers:postgresql to v1.20.4 (#27)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pom.xml

@@ -72,7 +72,7 @@
         <lib.junit-jupiter.version>5.11.3</lib.junit-jupiter.version>
         <lib.postgresql.version>42.7.4</lib.postgresql.version>
         <lib.slf4j.version>2.0.16</lib.slf4j.version>
-        <lib.testcontainers.version>1.20.3</lib.testcontainers.version>
+        <lib.testcontainers.version>1.20.4</lib.testcontainers.version>
 
         <!-- Default SCM Properties -->
         <scm.connection>scm:git:ssh://git@github.com/nscuro/datanucleus-postgresql.git</scm.connection>