Log Message:
databases/php-mongodb: update to 1.9.1

1.9.1 (2021-04-07)

Bug
* [PHPC-1713] - Ensure Cursor::current returns null on invalid positions
* [PHPC-1748] - Cursor::key returns valid values on invalid positions
* [PHPC-1774] - platform field in connection meta data cuts off PHP version
* [PHPC-1775] - php_phongo_dbpointer_init uses incorrect size for strncpy
* [PHPC-1793] - Compile failure with PHP's master branch (8.1-dev)
* [PHPC-1801] - Fix arginfo for Manager::selectServer

Task
* [PHPC-1739] - Move CI from travis-ci to GitHub Actions
* [PHPC-1808] - Upgrade libbson and libmongoc to 1.17.4

Improvement
* [PHPC-1795] - Remove usages of xtrace in shell scripts