Upgrade arm-none-eabi compiler

It was 5 years out of date and didn't fully support C++20.

In doing so, flip off "freestanding" mode for the cortex-m4f compiler's
use of libstdc++.
This is because some libraries appear to have been using STL headers
that cannot be safely linked against in freestanding mode (e.g.,
<ostream>). I am unsure why the prior compiler was not catching this.
If this becomes a problem, we can disable it.

Change-Id: Ie08ce2c089f787b0433a761ad2242dcd2a516404
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/tools/dependency_rewrite b/tools/dependency_rewrite
index 2cc90cf..2d2e610 100644
--- a/tools/dependency_rewrite
+++ b/tools/dependency_rewrite
@@ -3,6 +3,7 @@
 block *
 rewrite maven.ctr-electronics.com/(.*) software.frc971.org/Build-Dependencies/maven.ctr-electronics.com/$1
 rewrite github.com/(.*) software.frc971.org/Build-Dependencies/github.com/$1
+rewrite developer.arm.com/(.*) software.frc971.org/Build-Dependencies/developer.arm.com/$1
 rewrite dl.google.com/(.*) software.frc971.org/Build-Dependencies/dl.google.com/$1
 rewrite mirror.bazel.build/(.*) software.frc971.org/Build-Dependencies/mirror.bazel.build/$1
 rewrite nodejs.org/(.*) software.frc971.org/Build-Dependencies/nodejs.org/$1