Add Drupal 10 compatibility

Hi rp7,

I tried to apply and test your patch but your patch did not apply successfully

    "ext-elastic_apm": "*",
    "drupal/core": "^8.8 || ^9",
    "nipwaayoni/elastic-apm-php-agent": "^7.5"
  },
  "patches": {

error: patch failed: composer.json:6
error: composer.json: patch does not apply
Checking patch elastic_apm.info.yml...
error: while searching for:
type: module
description: Provides integration with the PHP agent for Elastic's APM product.
package: Performance
core_version_requirement: ^8.8 || ^9
# @I Review dependency on Path Alias module
#    type     : bug
#    priority : low

error: patch failed: elastic_apm.info.yml:2
error: elastic_apm.info.yml: patch does not apply

Works fine on my end? (current version of the 2.x branch)

$ patch -p1 < elastic_apm-drupal_10_compatibility-3391080-2.patch
patching file composer.json
patching file elastic_apm.info.yml

Are you using the 2.x version to apply this to?

I found some more usages of deprecated (and in D10 removed) code.