Add deprecation notice to README (#26)

README.md

@@ -6,10 +6,59 @@ GitHub Action that enables you to upload your test coverage data to DeepSource e
 
 If you're not using DeepSource yet, [get started for free](https://deepsource.io/signup?utm_source=githubmarketplace&utm_medium=organic).
 
+## Notice
+
+If you’re using the Test coverage action, we recommend switching to using the DeepSource CLI directly.
+To do this, rather than using the `test-coverage-action` step, you can do the following:
+
+```yaml
+steps:
+  - name: Checkout code
+    uses: actions/checkout@v2
+    with:
+      ref: ${{ github.event.pull_request.head.sha }}
+
+  # Run your tests here ...
+
+  - name: Report test-coverage to DeepSource
+    run: |
+      # Install the CLI
+      curl https://deepsource.io/cli | sh
+
+      # Send the report to DeepSource
+      ./bin/deepsource report --analyzer test-coverage --key <language> --value-file <path/to/coverage/file>
+```
+
+If you want to continue using the Test coverage action, please add a step before the test coverage action, to add a
+`safe.directory` parameter to your `.gitconfig`:
+
+```yaml
+steps:
+  - name: Checkout code
+    uses: actions/checkout@v2
+    with:
+      fetch-depth: 50
+      ref: ${{ github.event.pull_request.head.sha }}
+
+  # ADD THIS STEP
+  - name: Add git safe.directory for container
+    run: |
+      mkdir -p /home/runner/work/_temp/_github_home
+      printf "[safe]\ndirectory = /github/workspace" > /home/runner/work/_temp/_github_home/.gitconfig
+
+  - name: Report test-coverage to DeepSource
+    uses: deepsourcelabs/test-coverage-action@master
+    with:
+      ... The rest of your config is explained in Usage section.
+```
+
+Read this [Discuss post](https://discuss.deepsource.io/t/breaking-deepsource-test-coverage-github-action/507) for more information.
 
 ## Usage
 
-This Action assumes that the coverage file has already been generated after the tests have run. To integrate it in your workflow, define a step which refers to this Action in your `workflow.yml` file. We recommend that you use `@master`as the ref.
+This Action assumes that the coverage file has already been generated after the tests have run. To integrate it in your workflow, define a step which refers to this Action in your `workflow.yml` file. We recommend that you use `@master` as the ref.
+
+Ensure that you have added the `DEEPSOURCE_DSN` secret in your GitHub repository. It is available under **Settings → Reporting tab** of the repository page on DeepSource.
 
 ```yaml
 steps:
@@ -25,7 +74,7 @@ The possible inputs to this action are:
 
 * `key` (string, **required**): Programming language shortcode for which coverage is reported. Allowed values are: `python`, `go`.
 * `coverage-file` (string, **required**): Path to the coverage data file. e. g. `coverage.xml`
-* `dsn` (string, **required**): DeepSource DSN of this repository. It is available under **Settings → Reporting tab** of the repository page on DeepSource.
+* `dsn` (string, **required**): DeepSource DSN of this repository.
 * `fail-ci-on-error` (boolean): Should the CI build fail if there is an error while uploading the report to DeepSource? Allowed values are: `true`, `false`. This is set to `false` by default.
 
 ## License