fix:(rumqttc): Remove tls default provider from dependencies

[tlevora]

Updating 'rustls-webpki' to 0.103.0 removes default ring tls-provider from 'rustls-webpki' dependency and allows to specifically choose between 'ring' and 'aws-lc-rs'. Consider this commit fixing usage of 'use-rustls-no-provider' feature.

[giridher-art]

@tlevora this looks good , but does it break any clients that depend on use-rustls feature ? and i try to review it ASAP

[tlevora]

@tlevora this looks good , but does it break any clients that depend on use-rustls feature ? and i try to review it ASAP

@giridher-art, you are right this is a breaking change. It basically removes all that ring verification algorithms from ALL_VERIFICATION_ALGS in rustls-webpki if they are not added with an appropriate feature flag in any other dependency.

According to this issue what is the proper solution? Shall I just modify CHANGELOG.md record and a commit message?

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Then there is a question whether this is a good approach or not. If this commit will be applied as it is and a user of rumqttc will want to use either ring or aws-lc, he/she will need to add the rustls-webpki to his/her Cargo.toml as a dependency with the proper feature flag (either ring or aws_lc_rs).

Another solution could be adding another two feature flags to rumqttc:

[features]
# this is a current solution
use-rustls-no-provider = ["dep:tokio-rustls", "dep:rustls-webpki", "dep:rustls-pemfile", "dep:rustls-native-certs"]
# proposed features
use-rustls-ring = ["rustls-webpki?/ring"]
use-rustls-aws-lc = ["rustls-webpki?/aws_lc_rs"]

Then a user of rumqttc will be able to choose between ring and aws-lc in rustls-webpki dependency directly.