docs: start marking plugins and features with Concord version

docs/plugins-v2/asserts.md

@@ -7,6 +7,8 @@ description: Plugin makes it easy to add validation to your flows
 
 # {{ page.title }}
 
+_Available since version 2.19.0_
+
 The `asserts` task allows you to verify conditions within your flows. 
 It ensures that required variables, inputs, or states are correctly set during process execution. 
 If a condition fails, the flow will terminate with an error, preventing further execution

docs/plugins-v2/mocks.md

@@ -7,6 +7,8 @@ description: Safely and efficiently simulate behavior, verify interactions, and
 
 # {{ page.title }}
 
+_Available since version 2.19.0_
+
 - [Usage](#usage)
 - [How to mock a Task](#how-to-mock-a-task)
 - [How to Mock a Task method](#how-to-mock-a-task-method)

docs/processes-v2/flows.md

@@ -1090,6 +1090,8 @@ flows:
 
 ### Testing in Concord
 
+_Available since version 2.19.0_
+
 Testing in Concord offers a comprehensive and flexible approach by leveraging powerful tools like
 [mocks](../plugins-v2/mocks.html),
 the [verify task](../plugins-v2/mocks.html#how-ot-verify-task-calls),

docs/processes-v2/index.md

@@ -344,6 +344,8 @@ Any value type that can be represented as JSON is supported.
 
 ### Dry-run mode
 
+_Available since version 2.19.0_
+
 The dry-run mode allows you to execute a process without making any dangerous side-effects.
 This is useful for testing and validating the flow logic before running it in production.