Adds codecov coverage result badge to README.md (#75)

Author: aykut-bozkurt

.github/workflows/ci.yml

@@ -129,6 +129,6 @@ jobs:
         if: ${{ env.PG_MAJOR }} == 17
         uses: codecov/codecov-action@v4
         with:
-          fail_ci_if_error: false
+          fail_ci_if_error: true
           files: ./lcov.info
           token: ${{ secrets.CODECOV_TOKEN }}

README.md

@@ -3,6 +3,7 @@
 > Copy from/to Parquet files in PostgreSQL!
 
 [![CI lints and tests](https://github.com/CrunchyData/pg_parquet/actions/workflows/ci.yml/badge.svg)](https://github.com/CrunchyData/pg_parquet/actions/workflows/ci.yml)
+[![codecov](https://codecov.io/gh/CrunchyData/pg_parquet/graph/badge.svg?token=6BPS0DSKJ2)](https://codecov.io/gh/CrunchyData/pg_parquet)
 
 `pg_parquet` is a PostgreSQL extension that allows you to read and write [Parquet files](https://parquet.apache.org), which are located in `S3` or `file system`, from PostgreSQL via `COPY TO/FROM` commands. It depends on [Apache Arrow](https://arrow.apache.org/rust/arrow/) project to read and write Parquet files and [pgrx](https://github.com/pgcentralfoundation/pgrx) project to extend PostgreSQL's `COPY` command.