MDL-70302 core: Update the lib's readme, xml and upgrade files

lib/spout/readme_moodle.txt

@@ -1,9 +1,14 @@
-Description of Spout library import 3.0.1
+Description of Spout library import
 =========================================
 * Download / Clone from https://github.com/box/spout/
 * Only include the src/Spout directory.
 * Update lib/thirdpartylibs.xml with the latest version.
 
+2020/12/07
+----------
+Update to v3.1.0 (MDL-70302)
+by Peter Dias <[email protected]>
+
 2019/06/17
 ----------
 Update to v3.0.1 (MDL-65762)

lib/thirdpartylibs.xml

@@ -235,7 +235,7 @@
     <location>spout</location>
     <name>Spout</name>
     <license>Apache</license>
-    <version>3.0.1</version>
+    <version>3.1.0</version>
     <licenseversion>2.0</licenseversion>
   </library>
   <library>

lib/upgrade.txt

@@ -15,6 +15,7 @@ information provided here is intended especially for developers.
 * Behat timeout constants behat_base::TIMEOUT, EXTENDED_TIMEOUT, and REDUCED_TIMEOUT, which were deprecated in 3.7, have been removed.
 * \core_table\local\filter\filterset::JOINTYPE_DEFAULT is being changed from 1 (ANY) to 2 (ALL). Filterset implementations
   can override the default filterset join type by overriding \core_table\local\filter\filterset::get_join_type() instead.
+* Spout has been upgraded to the latest version - 3.1.0
 
 === 3.10 ===
 * PHPUnit has been upgraded to 8.5. That comes with a few changes: