mbedtls_mpi_read_string("-0") no longer produces a "negative zero"

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/mpi_read_negative_zero.txt b/ChangeLog.d/mpi_read_negative_zero.txt
new file mode 100644
index 0000000..f540fbf
--- /dev/null
+++ b/ChangeLog.d/mpi_read_negative_zero.txt
@@ -0,0 +1,3 @@
+Bugfix
+   * Fix mbedtls_mpi_read_string on "-0" returning a ``negative zero'' object,
+     which the library does fully consistently treat as equal to zero.