Add libpcre2-dev as it is needed by latest r-devel

When the image is r-ver:devel is built without libpcre2-dev,
the following issue is generated.

```
checking whether PCRE support suffices... no
configure: error: PCRE2 library and headers are required, or use --with-pcre1 and PCRE >= 8.32 with UTF-8 support
/bin/sh: 1: Rscript: not found
```

This allows a clean build