doc: Update README for coveralls.lcov

README.md

@@ -86,6 +86,7 @@ end
     - [[mix coveralls.html] Show coverage as HTML report](#mix-coverallshtml-show-coverage-as-html-report)
     - [[mix coveralls.json] Show coverage as JSON report](#mix-coverallsjson-show-coverage-as-json-report)
     - [[mix coveralls.xml] Show coverage as XML report](#mix-coverallsxml-show-coverage-as-xml-report)
+    - [[mix coveralls.lcov] Show coverage as lcov report (Experimental)](#mix-coverallslcov-show-coverage-as-lcov-report)
   - [coveralls.json](#coverallsjson)
       - [Stop Words](#stop-words)
       - [Exclude Files](#exclude-files)
@@ -357,6 +358,13 @@ Output to the shell is the same as running the command `mix coveralls` (to suppr
 
 Output reports are written to `cover/excoveralls.xml` by default, however, the path can be specified by overwriting the `"output_dir"` coverage option.
 
+### [mix coveralls.lcov] Show coverage as lcov report (Experimental)
+This task displays coverage information at the line level formatted as a lcov.
+The report follows a format supported by several code coverage services like VSCode extension(`ryanluker.vscode-coverage-gutters`).
+Output to the shell is the same as running the command `mix coveralls` (to suppress this output, add `"print_summary": false` to your project's `coveralls.json` file). In a similar manner to `mix coveralls.detail`, reported source code can be filtered by specifying arguments using the `--filter` flag.
+
+Output reports are written to `cover/lcov.info` by default, however, the path can be specified by overwriting the `"output_dir"` coverage option.
+
 ## coveralls.json
 `coveralls.json` provides settings for excoveralls.