🧹(docs): wider, optimised banner (ethereum#1142)

Author: raxhvl

docs/img/execution_spec_tests.jpg

@@ -1,7 +1,7 @@
 # Execution Spec Tests
 
 <figure markdown>  <!-- markdownlint-disable MD033 (MD033=no-inline-html) -->
-  ![Execution Spec Tests Logo](img/execution_spec_tests.png){width="400"}
+  ![Execution Spec Tests Logo](img/execution_spec_tests.jpg)
 </figure>
 
 @ethereum/execution-spec-tests is both a collection of test cases and a framework in Python to generate tests for Ethereum execution clients implemented.

docs/img/execution_spec_tests.png

@@ -257,6 +257,7 @@ intermidiate
 javascripts
 jimporter
 joinpath
+jpg
 jq
 js
 json
@@ -830,4 +831,4 @@ EB
 EF
 F6
 FC
-ef01
+ef01