fix: add back empty tls feature

Signed-off-by: Jeremie Drouet <[email protected]>

Author: jdrouet

opentelemetry-otlp/Cargo.toml

@@ -76,10 +76,11 @@ zstd-tonic = ["tonic/zstd"]
 # http compression
 gzip-http = ["flate2"]
 zstd-http = ["zstd"]
-tls-aws-lc = ["tonic/tls-aws-lc"]
-tls-ring = ["tonic/tls-ring"]
-tls-roots = ["tonic/tls-native-roots"]
-tls-webpki-roots = ["tonic/tls-webpki-roots"]
+tls = []
+tls-aws-lc = ["tls", "tonic/tls-aws-lc"]
+tls-ring = ["tls", "tonic/tls-ring"]
+tls-roots = ["tls", "tonic/tls-native-roots"]
+tls-webpki-roots = ["tls", "tonic/tls-webpki-roots"]
 
 # http binary
 http-proto = ["prost", "opentelemetry-http", "opentelemetry-proto/gen-tonic-messages", "http", "trace", "metrics"]