docs: release: Add release notes

Adds release notes for various recent changes

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
diff --git a/docs/release-notes.d/zephyr-mbedtls-kconfig.md b/docs/release-notes.d/zephyr-mbedtls-kconfig.md
new file mode 100644
index 0000000..d7914cb
--- /dev/null
+++ b/docs/release-notes.d/zephyr-mbedtls-kconfig.md
@@ -0,0 +1 @@
+- Zephyr: Prevent MBEDTLS Kconfig selection when tinycrypt is used.