Update codecov

- Exclude *glacier & DAO forks from coverage
- Add codecov badge to README

Author: Carsons-Eels

README.md

@@ -1,6 +1,7 @@
 # Ethereum Execution Client Specifications
 
 [![GitPOAP Badge](https://public-api.gitpoap.io/v1/repo/ethereum/execution-specs/badge)](https://www.gitpoap.io/gh/ethereum/execution-specs)
+[![codecov](https://codecov.io/gh/ethereum/execution-specs/graph/badge.svg?token=0LQZO56RTM)](https://codecov.io/gh/ethereum/execution-specs)
 
 ## Description
 

pyproject.toml

@@ -17,6 +17,12 @@ markers = [
     "evm_tools: marks tests as evm_tools (deselect with '-m \"not evm_tools\"')",
 ]
 
+[tool.coverage.run]
+omit = [
+    "*/ethereum/*_glacier/*",
+    "*/ethereum/dao_fork/*",
+]
+
 [tool.docc]
 context = [
     "docc.references.context",

tox.ini

@@ -22,7 +22,12 @@ commands =
     pytest \
         -m "not slow" \
         -n auto --maxprocesses 5 \
-        --cov=ethereum --cov-report=term --cov-report "xml:{toxworkdir}/coverage.xml" \
+        --cov-config=pyproject.toml \
+        --cov=ethereum \
+        --cov-report=term \
+        --cov-report "xml:{toxworkdir}/coverage.xml" \
+        --no-cov-on-fail \
+        --cov-branch \
         --ignore-glob='tests/fixtures/*' \
         --basetemp="{temp_dir}/pytest"