plugin: add Apache 2 license to known licenses

the licence in gstreamer/subprojects/gstreamer/gst/gstplugin.c
currently is defined to be one of:
LGPL GPL QPL GPL/QPL MPL BSD MIT/X11 0BSD Proprietary
The open source project for the kinesis plugin is using an
Apache 2.0 license. Because "Apache 2.0" is not one of the
supported licenses it automatically falls back to Proprietary.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2514>

Author: clogwog

subprojects/gstreamer/gst/gstplugin.c

@@ -95,6 +95,8 @@ static char *_gst_plugin_fault_handler_filename = NULL;
  * MIT/X11: https://opensource.org/licenses/MIT
  * 3-clause BSD: https://opensource.org/licenses/BSD-3-Clause
  * Zero-Clause BSD: https://opensource.org/licenses/0BSD
+ * Apache License 2.0: http://www.apache.org/licenses/LICENSE-2.0 (Since: 1.22)
+
  * FIXME: update to use SPDX identifiers, or just remove entirely
  */
 static const gchar known_licenses[] = "LGPL\000"        /* GNU Lesser General Public License */
@@ -106,6 +108,7 @@ static const gchar known_licenses[] = "LGPL\000"        /* GNU Lesser General Pu
     "BSD\000"                   /* 3-clause BSD license */
     "MIT/X11\000"               /* MIT/X11 license */
     "0BSD\000"                  /* Zero-Clause BSD */
+    "Apache 2.0\000"            /* Apache License 2.0 */
     "Proprietary\000"           /* Proprietary license */
     GST_LICENSE_UNKNOWN;        /* some other license */
 
@@ -1487,19 +1490,19 @@ gst_plugin_list_free (GList * list)
  * ENV + *xyz   same as above, but xyz acts as suffix filter
  * ENV + xyz*   same as above, but xyz acts as prefix filter (is this needed?)
  * ENV + *xyz*  same as above, but xyz acts as strstr filter (is this needed?)
- * 
+ *
  * same as above, with additional paths hard-coded at compile-time:
  *   - only check paths + ... if ENV is not set or yields not paths
  *   - always check paths + ... in addition to ENV
  *
  * When user specifies set of environment variables, he/she may also use e.g.
  * "HOME/.mystuff/plugins", and we'll expand the content of $HOME with the
- * remainder 
+ * remainder
  */
 
 /* we store in registry:
  *  sets of:
- *   { 
+ *   {
  *     - environment variables (array of strings)
  *     - last hash of env variable contents (uint) (so we can avoid doing stats
  *       if one of the env vars has changed; premature optimisation galore)