chore: Use accurate development version number

DESCRIPTION

 Type: Package
 Package: RFSurrogates
 Title: Surrogate Minimal Depth Variable Importance
-Version: 0.3.4
+Version: 0.3.3.9000
 Authors@R: c(
     person("Stephan", "Seifert", , "stephan.seifert@uni-hamburg.de", role = c("aut", "cre"),
            comment = c(ORCID = "0000-0003-2567-5728")),

NEWS.md

-# RFSurrogates 0.3.4
-
-<!-- News Style-guide: https://style.tidyverse.org/news.html -->
+# RFSurrogates (development version)
 
 * `var.select.smd()`, `var.select.md()`, `var.relations()`, `var.relations.mfi()`: Made several improvements to developer experience:
   * `create.forest` now defaults to `is.null(forest)`, so it will automatically be `TRUE` if no forest is provided, and `FALSE` otherwise.