Switch to TLS 1.2 as minimum requirement

According to https://tools.ietf.org/id/draft-ietf-tls-oldversions-deprecate-06.txt

TEST=Not applicable, config change.

Closes #41135
#41135

GitOrigin-RevId: e1dc037
Change-Id: Ic8340eee7fa26846302727672ca7989ce1e93c99
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/140481
Commit-Queue: Michael Thomsen <[email protected]>
Reviewed-by: Siva Annamalai <[email protected]>

Author: loganaden

runtime/bin/security_context.cc

@@ -807,7 +807,7 @@ void FUNCTION_NAME(SecurityContext_Allocate)(Dart_NativeArguments args) {
   SSLFilter::InitializeLibrary();
   SSL_CTX* ctx = SSL_CTX_new(TLS_method());
   SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, SSLCertContext::CertificateCallback);
-  SSL_CTX_set_min_proto_version(ctx, TLS1_VERSION);
+  SSL_CTX_set_min_proto_version(ctx, TLS1_2_VERSION);
   SSL_CTX_set_cipher_list(ctx, "HIGH:MEDIUM");
   SSLCertContext* context = new SSLCertContext(ctx);
   Dart_Handle err = SetSecurityContext(args, context);