Replace reference to master
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/README.md b/README.md
index d226260..b70c67e 100644
--- a/README.md
+++ b/README.md
@@ -250,7 +250,7 @@
- `tests/scripts/depends.py` test builds in configurations with a single curve, key exchange, hash, cipher, or pkalg on.
- `tests/scripts/all.sh` runs a combination of the above tests, plus some more, with various build options (such as ASan, full `mbedtls_config.h`, etc).
-Instead of manually installing the required versions of all tools required for testing, it is possible to use the Docker images from our CI systems, as explained in [our testing infrastructure repository](https://github.com/Mbed-TLS/mbedtls-test/blob/master/README.md#quick-start).
+Instead of manually installing the required versions of all tools required for testing, it is possible to use the Docker images from our CI systems, as explained in [our testing infrastructure repository](https://github.com/Mbed-TLS/mbedtls-test/blob/main/README.md#quick-start).
Porting Mbed TLS
----------------