fix: add GIT_SSL_CAINFO to tracing proxy env vars (#8502)

Git uses libcurl with GnuTLS on Debian, which doesn't read
SSL_CERT_FILE or CURL_CA_BUNDLE for CA trust. When the OTEL tracing
proxy is enabled, git clone fails with "certificate signer not trusted"
because it can't verify the proxy's MITM certificate.

Adding GIT_SSL_CAINFO pointing to the proxy CA cert fixes this.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

backend/windmill-worker/src/worker.rs

@@ -965,6 +965,7 @@ async fn get_otel_tracing_proxy_envs(
             TRACING_PROXY_CA_CERT_PATH.to_string(),
         ),
         ("CURL_CA_BUNDLE", TRACING_PROXY_CA_CERT_PATH.to_string()),
+        ("GIT_SSL_CAINFO", TRACING_PROXY_CA_CERT_PATH.to_string()),
         ("DENO_CERT", TRACING_PROXY_CA_CERT_PATH.to_string()),
     ])
 }