Enable TLS 1.0 and 1.1 internally (#11837)

BoringSSL bumped the default minimum TLS to 1.2. ATS is affected by this change because it expects that TLS 1.0 and 1.1 are enabled by default.
https://boringssl.googlesource.com/boringssl/+/e95b0cad901abd49755d2a2a2f1f6c3e87d12b94

Although this change enables the old versions internally, the default ATS setting disables those.
Only users who enable the old versions and use newer BoringSSL are affected.

src/iocore/net/SSLUtils.cc

@@ -1231,6 +1231,7 @@ SSLMultiCertConfigLoader::init_server_ssl_ctx(CertLoadData const &data, const SS
     Dbg(dbg_ctl_ssl_load, "Creating new context %p cert_count=%ld initial: %s", ctx, cert_names_list.size(),
         cert_names_list[0].c_str());
 
+    SSL_CTX_set_min_proto_version(ctx, TLS1_VERSION);
     SSL_CTX_set_options(ctx, _params->ssl_ctx_options);
 
     if (_params->server_tls_ver_min >= 0 || _params->server_tls_ver_max >= 0) {