chore: Allow to build with rustls

ring 0.17 supports RISC-V, so building Pulsar with rustls instead
of OpenSSL is possible.

Choice of the TLS library is exposed by the following features
in the `smtp-notifier` crate:

* `native-tls` - uses the native TLS library in the system, usually
  OpenSSL. Enabled by default.
* `boring-tls` - uses BoringSSL. Disabled by default.
* `rustls-tls` - uses rustls. Disabled by default.

When building Pulsar with Cargo, the native TLS is going to be used.

However, for binary builds for Github releases, rustls is being
used, since it's always statically built and doesn't require any
runtime dependencies from the users.

.github/workflows/build.yaml

@@ -19,20 +19,19 @@ jobs:
           - target: x86_64-unknown-linux-gnu
             args: "--features full"
 
-          # For `musl` builds openssl must be vendored
+          # For `musl` builds, we need to use rustls
           - target: x86_64-unknown-linux-musl
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features full --features rustls-tls"
 
           - target: aarch64-unknown-linux-gnu
             args: "--features full"
 
-          # For `musl` builds openssl must be vendored
+          # For `musl` builds, we need to use rustls
           - target: aarch64-unknown-linux-musl
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features full --features rustls-tls"
 
-          # Dependencies of `xtask` might fail to build on riscv64.
           - target: riscv64gc-unknown-linux-gnu
-            args: "--features full --exclude xtask"
+            args: "--features full"
 
     steps:
       - name: Code checkout

.github/workflows/quality.yaml

@@ -52,16 +52,14 @@ jobs:
           - target: x86_64-unknown-linux-gnu
             args: "--features full"
 
-          # For `musl` builds openssl must be vendored
           - target: x86_64-unknown-linux-musl
-            args: "--features full --features openssl-vendored"
+            args: "--features full"
 
           - target: aarch64-unknown-linux-gnu
             args: "--features full"
 
-          # For `musl` builds openssl must be vendored
           - target: aarch64-unknown-linux-musl
-            args: "--features full --features openssl-vendored"
+            args: "--features full"
 
           # Dependencies of `xtask` might fail to build on riscv64.
           - target: riscv64gc-unknown-linux-gnu

.github/workflows/release.yaml

@@ -53,25 +53,25 @@ jobs:
       matrix:
         platform:
           - target: x86_64-unknown-linux-gnu
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features smtp-notifier/rustls-tls"
             docker:
               base-image: debian:bookworm
               platform: linux/amd64
 
           - target: x86_64-unknown-linux-musl
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features smtp-notifier/rustls-tls"
 
           - target: aarch64-unknown-linux-gnu
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features smtp-notifier/rustls-tls"
             docker:
               base-image: debian:bookworm
               platform: linux/arm64
 
           - target: aarch64-unknown-linux-musl
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features smtp-notifier/rustls-tls"
 
           - target: riscv64gc-unknown-linux-gnu
-            args: "--features full --features openssl-vendored"
+            args: "--no-default-features --features smtp-notifier/rustls-tls"
             docker:
               base-image: debian:sid
               platform: linux/riscv64