chore: increase Cargo network retries

Quite often (at least 6 times today), tests fail because cargo fails to
 download a package.
This commit sets the retries to 10 (up to the default of 3).

Signed-off-by: Marco Marangoni <mamarang@amazon.com>

Author: marco-marangoni

.cargo/config.toml

@@ -6,6 +6,7 @@ rustflags = [
 
 [net]
 git-fetch-with-cli = true
+retry = 10
 
 [env]
 AWS_LC_SYS_NO_JITTER_ENTROPY = "1"