Fix incorrect variable syntax Update fetch-blocks.sh

[famouswizard]

PR Description

In the provided script, there was an issue with the URL used for downloading the state. Specifically, the following line was incorrect:

curl --fail -H 'Accept: application/octet-stream' http://localhost:$PORT/eth/v2/debug/beacon/states/{$START} -o "${OUT}/state.ssz" &

The variable $START was incorrectly enclosed in curly braces {}. In Bash, variable substitution requires the use of ${} (with no additional characters inside the braces), and thus the correct syntax is:

curl --fail -H 'Accept: application/octet-stream' http://localhost:$PORT/eth/v2/debug/beacon/states/${START} -o "${OUT}/state.ssz" &

Importance of the fix:

This fix is critical because the incorrect syntax would prevent the variable $START from being substituted properly within the URL. As a result, the script would fail to download the required state, potentially causing issues with subsequent operations or making the script unreliable. By correcting this syntax, the variable is properly interpolated, ensuring the script functions as intended and that the state is downloaded correctly.

Summary:

• Fixed the incorrect variable syntax in the state download URL.
• Ensured correct variable interpolation for Bash compatibility.

Documentation

• I thought about documentation and added the doc-change-required label to this PR if updates are required.

Changelog

• I thought about adding a changelog entry, and added one if I deemed necessary.

[CLAassistant]

All committers have signed the CLA.

[rolfyone]

LGTM - thanks for the contribution, and writeup.