build: unpin OpenSSL version and update to OpenSSL 3.3.0

Previously OpenSSL was pinned due to problems
with Zig toolchain used back then
and then not unpinned even after switching from Zig to Nix
due to <alexcrichton/openssl-src-rs#235>.
The problem should be fixed now
and we can try to unpin OpenSSL again.

Cargo.toml

@@ -104,14 +104,6 @@ toml = "0.8"
 url = "2"
 uuid = { version = "1", features = ["serde", "v4"] }
 
-# Pin OpenSSL to 3.1 releases.
-# OpenSSL 3.2 has a regression tracked at <https://github.com/openssl/openssl/issues/23376>
-# which results in broken `deltachat-rpc-server` binaries when cross-compiled using Zig toolchain.
-# See <https://github.com/deltachat/deltachat-core-rust/issues/5206> for Delta Chat issue.
-# According to <https://www.openssl.org/policies/releasestrat.html>
-# 3.1 branch will be supported until 2025-03-14.
-openssl-src = "~300.1"
-
 [dev-dependencies]
 ansi_term = "0.12.0"
 anyhow = { version = "1", features = ["backtrace"] } # Enable `backtrace` feature in tests.