MDL-70309 libraries: upgrade mongodb integration files

cache/stores/mongodb/lib.php

@@ -158,7 +158,7 @@ class cachestore_mongodb extends cache_store implements cache_is_configurable {
      * @return bool
      */
     public static function are_requirements_met() {
-        return version_compare(phpversion('mongodb'), '1.5', 'ge');
+        return version_compare(phpversion('mongodb'), '1.8', 'ge');
     }
 
     /**

cache/stores/mongodb/readme_moodle.txt

@@ -7,5 +7,6 @@ Import procedure:
 - Copy all the files and folders from the folder mongodb/src in the cache/stores/mongodb/MongoDB directory.
 - Copy the license file from the project root.
 - Update thirdpartylibs.xml with the latest version.
+- Check the minim php driver version in https://docs.mongodb.com/drivers/php#compatibility and change the value in the "are_requirements_met" method if necessary.
 
-This version (1.5.1) requires PHP mongodb extension >= 1.6.0
+This version (1.8.0) requires PHP mongodb extension >= 1.8.0

cache/stores/mongodb/thirdpartylibs.xml

@@ -4,7 +4,7 @@
     <location>MongoDB</location>
     <name>MongoDB PHP Library</name>
     <license>Apache</license>
-    <version>1.5.1</version>
+    <version>1.8.0</version>
     <licenseversion>2.0</licenseversion>
   </library>
 </libraries>