Rename VSI prefix to vsiriopener

Pin to 2.0.0rc1 exactly for this release

Do not resolve output files to absolute paths

New pre-release date

This is 1.3.9

This is 1.3.8.post2

Update change log, this is 1.3.8.post1

Cast pointer to buffer as char * before arithmetic

This is 1.3.7

This is 1.3.6