update example bootstrap list to use newer nodes

[mburns]

Description

This updates the example bootstrap nodes to use the more generic bootstrap.libp2p.io and uses a newer set of bootstrap keys. These machines have been up and running for several months.

Why

The IPFS Infra team would like to deprecate the foo-1.bootstrap.libp2p.io pattern in favor of just bootstrap.libp2p.io, to decouple a node's geography from the peer_id.

connected to libp2p/js-libp2p#772

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• Firmware version:
• Hardware:
• Toolchain:
• SDK:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

This PR template comes from https://github.com/embeddedartistry/templates

[mburns]

closing due to inactivity