bump x.y.z version to even y prior to creation of RELEASE_3_21 branch

Author: lshep

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: SingleCellMultiModal
 Title: Integrating Multi-modal Single Cell Experiment datasets
-Version: 1.19.2
+Version: 1.20.0
 Authors@R: c(
     person("Marcel", "Ramos", , "[email protected]",
         c("aut", "cre"), c(ORCID = "0000-0002-3242-0582")