ci: pin idna_adapter dep to fix reqest with MSRV 1.75

[notmandatory]

Description

The bdk_esplora crate depends on reqwest which now pins it's idna_adapter version to support newer versions of the url crate when testing with it's MSRV. I fixed our CI 1.75 MSRV build by also pinning the idna_adapter.

Notes to the reviewers

The MSRV break was fixed by the reqwest team with seanmonstar/reqwest#2470.

This change was made 2 mo ago, I'm not sure why our CI only broke now.

Changelog notice

• Pin idna_adapter dep to fix reqwest with MSRV 1.75.

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

[notmandatory]

I moved this back to DRAFT, I may have found a smaller change to fix this.

[notmandatory]

Ready to review/merge.

[evanlinjin]

ACK d4670b3