cli: release 3.20

[bassosimone]

Ideally, this release would include an improved Web Connectivity v0.5. If we fail to merge these changes, it would still be nice to release with upgraded dependencies. Supporting go1.21 would also be great, if possible. 🙏

Done

• [x] probe-cli: update github.com/ooni/probe-assets dependency https://github.com/ooni/probe-cli/pull/1390 https://github.com/ooni/probe-cli/pull/1426
• [x] oohttp: merge with upstream if needed https://github.com/ooni/oohttp/pull/51 https://github.com/ooni/probe-cli/pull/1391 https://github.com/ooni/probe-cli/pull/1427
• [x] oocrypto: merge with upstream if needed https://github.com/ooni/oocrypto/pull/23 https://github.com/ooni/probe-cli/pull/1391 https://github.com/ooni/probe-cli/pull/1427
• [x] probe-cli: update the Go version mentioned in the Readme.md file https://github.com/ooni/probe-cli/pull/1391 https://github.com/ooni/probe-cli/pull/1427
• [x] probe-cli: update GOVERSION if needed: https://github.com/ooni/probe-cli/pull/1391 https://github.com/ooni/probe-cli/pull/1427
• [x] probe-cli: run ./script/updateminipipeline.bash https://github.com/ooni/probe-cli/pull/1429
• [x] probe-cli: update bundled certs (using go generate ./...) https://github.com/ooni/probe-cli/pull/1429
• [x] probe-cli: take a look at go report card https://github.com/ooni/probe-cli/pull/1429
• [x] probe-cli: update user-agent at internal/model/http.go https://github.com/ooni/probe-cli/pull/1429
• [x] probe-cli: update deps requiring update according to gomajor https://github.com/ooni/probe-cli/pull/1430 https://github.com/ooni/probe-cli/pull/1431 https://github.com/ooni/netem/pull/45 https://github.com/ooni/probe-cli/pull/1432 https://github.com/ooni/probe-cli/pull/1428
• [x] probe-cli: pin to the latest staging-client commit using go get -u -v https://github.com/ooni/probe-cli/pull/1430
• [x] probe-cli: update dependencies with go get -u -v -d ./... https://github.com/ooni/probe-cli/pull/1433
• [x] probe-cli: make sure we can build with go1.21 https://github.com/ooni/probe-cli/pull/1424
• [x] probe-cli: sync stunreachability targets with snowflake (see ./internal/stuninput)
• [x] probe-cli: update NDKVERSION, and MOBILE/android/ensure if needed
• [x] probe-cli: update cdeps https://github.com/ooni/probe-cli/pull/1434
• [x] probe-cli: go test -race -count 1 ./... must pass locally
• [x] probe-cli: make sure all workflows are green (yes, see https://github.com/ooni/probe-cli/pull/1434)
• [x] probe-cli: update internal/version/version.go https://github.com/ooni/probe-cli/commit/c34bdf63236e29171a8c0dd81fe4edcc8fffd991
• [x] probe-cli: tag a new version
• [x] probe-cli: update internal/version/version.go to be alpha https://github.com/ooni/probe-cli/pull/1439
• [x] probe-engine: run ./script/autoexport.bash: https://github.com/ooni/probe-engine/releases/tag/v0.27.0
• [x] debian: publish packages
• [x] iThena: notify about new release