ruby-addressable: update to 2.6.0.
Upstream changes (from CHANGELOG.md):
# Addressable 2.6.0
- added `tld=` method to allow assignment to the public suffix
- most `heuristic_parse` patterns are now case-insensitive
- `heuristic_parse` handles more `file://` URI variations
- fixes bug in `heuristic_parse` when uri starts with digit
- fixes bug in `request_uri=` with query strings
- fixes template issues with `nil` and `?` operator
- `frozen_string_literal` pragmas added
- minor performance improvements in regexps
- fixes to eliminate warnings
UnifiedSplitRaw
