Use codecov token in the build pipeline + Update readme (#10)

* use codecov token in the build pipeline

* add code coverage details to readme

* add a badge for codecov to the readme

* use upstream repo config instead of fork

Author: AdwaitChavan

.github/workflows/build.yml

@@ -135,4 +135,5 @@ jobs:
       - name: Upload Code Coverage Report
         uses: codecov/codecov-action@v4
         with:
-          files: ${{ github.workspace }}/build/reports/kover/report.xml
+          files: ${{ github.workspace }}/build/reports/kover/report.xml
+          token: ${{ secrets.CODECOV_TOKEN }}

README.md

@@ -1,5 +1,7 @@
 # Secure Gateway Tunneler
 
+[![codecov](https://codecov.io/github/salesforce/secure-pomerium-tunneler/graph/badge.svg?token=R0HHUDVA30)](https://codecov.io/github/salesforce/secure-pomerium-tunneler)
+
 <!-- Plugin description -->
 A Jetbrains Gateway plugin which handles authentication and tunneling through to a
 [Pomerium](https://pomerium.io) route for connecting to a IntelliJ backend.
@@ -14,10 +16,20 @@ links. This provider requires the following parameters in the links query parame
 2) `connectionKey`: A URL encoded join link provided by the backend.
 for example, by using `remote-dev-server.sh status`. It will be the one that looks like
 `tcp://127.0.0.1:5990#jt=...`
-3) `pomeriumInstance`: (Optional) a hostname of the pomerium instance to use. By default
+3) `pomeriumInstance`: (Optional) a hostname of the pomerium instance to use. By default,
 the `pomeriumRoute` will be used to connect, but if DNS does not point to pomerium, this can be used
 
 In addition, this plugin implements `GatewayConnector` to allow connecting using the 
 instance via the `jetbrains-gateway://` link without going through the browser (useful for testing)
 
+## Code Coverage
+
+This project uses [Codecov](https://about.codecov.io/) for test coverage metrics, integrated via GitHub Actions. 
+Coverage reports are generated on every build and uploaded to Codecov for visualization and tracking.
+
+For protected branches (e.g., main), a Codecov upload token is required and already configured as a 
+repository secret (`CODECOV_TOKEN`). If you fork this repository or set up a similar workflow, add your 
+own token as a secret and ensure coverage reports are generated at `build/reports/kover/report.xml`. 
+For more details, see the [Codecov docs](https://docs.codecov.com/docs/codecov-tokens).
+