Add setup for codecov (#5)

Author: javydevx

.codecov.yaml

@@ -0,0 +1,13 @@
+coverage:
+  status:
+    project:
+      default:
+        target: 80%
+        threshold: 1%
+        base: auto
+        if_not_found: success
+comment:
+  layout: "reach, diff, flags, files"
+  behavior: default
+  require_changes: true
+  after_n_builds: 1

README.md

@@ -2,7 +2,7 @@
 
 [![Go CI](https://github.com/javy99/problem-solving-golang/actions/workflows/ci.yml/badge.svg)](https://github.com/javy99/problem-solving-golang/actions/workflows/ci.yml)
 
-[![codecov](https://codecov.io/gh/javy99/problem-solving-golang/branch/master/graph/badge.svg?token=YOUR_CODECOV_TOKEN)](https://codecov.io/gh/javy99/problem-solving-golang)
+[![codecov](https://codecov.io/gh/javy99/problem-solving-golang/branch/master/graph/badge.svg?token=O2R79NNN6X)](https://codecov.io/gh/javy99/problem-solving-golang)
 
 # 🚀 NeetCode 150 in Go