Remove Core references

Replace Core references with Free tier.

doc/operations/incident_management/integrations.md

@@ -6,8 +6,8 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 # Alert integrations **(FREE)**
 
-> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/13203) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 12.4.
-> - [Moved](https://gitlab.com/gitlab-org/gitlab/-/issues/42640) to [GitLab Core](https://about.gitlab.com/pricing/) in 12.8.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/13203) in GitLab Ultimate 12.4.
+> - [Moved](https://gitlab.com/gitlab-org/gitlab/-/issues/42640) to GitLab Free in 12.8.
 
 GitLab can accept alerts from any source via a webhook receiver. This can be configured
 generically or, in GitLab versions 13.1 and greater, you can configure
@@ -16,7 +16,7 @@ to use this endpoint.
 
 ## Integrations list
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/245331) in [GitLab Core](https://about.gitlab.com/pricing/) 13.5.
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/245331) in GitLab Free 13.5.
 
 With Maintainer or higher [permissions](../../user/permissions.md), you can view
 the list of configured alerts integrations by navigating to
@@ -45,7 +45,7 @@ receive alert payloads in JSON format. You can always
 
 ### HTTP Endpoints **PREMIUM**
 
-> [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/4442) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.6.
+> [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/4442) in GitLab Premium 13.6.
 
 In [GitLab Premium](https://about.gitlab.com/pricing/), you can create multiple
 unique HTTP endpoints to receive alerts from any external source in JSON format,
@@ -140,7 +140,7 @@ Example payload:
 
 ## Triggering test alerts
 
-> [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/3066) in GitLab Core in 13.2.
+> [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/3066) in GitLab Free in 13.2.
 
 After a [project maintainer or owner](../../user/permissions.md)
 configures an integration, you can trigger a test
@@ -156,7 +156,7 @@ GitLab displays an error or success message, depending on the outcome of your te
 
 ## Automatic grouping of identical alerts **(PREMIUM)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/214557) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.2.
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/214557) in GitLab Premium 13.2.
 
 In GitLab versions 13.2 and greater, GitLab groups alerts based on their
 payload. When an incoming alert contains the same payload as another alert
@@ -170,7 +170,7 @@ If the existing alert is already `resolved`, GitLab creates a new alert instead.
 
 ## Link to your Opsgenie Alerts
 
-> [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/3066) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.2.
+> [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/3066) in GitLab Premium 13.2.
 
 WARNING:
 We are building deeper integration with Opsgenie and other alerting tools through