Tools: port iat-verifier to cbor2

The cbor module is unmaintained, with the last release in 2016[1]. The
cbor2 module however is under active development and was last released
just last month[2].

[1] https://pypi.org/project/cbor/#history
[2] https://pypi.org/project/cbor2/#history

Signed-off-by: Ross Burton <ross.burton@arm.com>
Change-Id: Ib24a88f19dea05fb9143afaa4bdf7ebdd5a2dda6
diff --git a/docs/getting_started/tfm_getting_started.rst b/docs/getting_started/tfm_getting_started.rst
index 5ea61b1..6c89b5d 100644
--- a/docs/getting_started/tfm_getting_started.rst
+++ b/docs/getting_started/tfm_getting_started.rst
@@ -370,7 +370,7 @@
     fw --> pyasn1
     fw --> yaml
     fw --> jinja2
-    fw --> cbor
+    fw --> cbor2
     fw --> click
     fw --> imgtool
     c_comp --> GCC
@@ -380,7 +380,7 @@
     pyasn1 --> python
     yaml --> python
     jinja2 --> python
-    cbor --> python
+    cbor2 --> python
     click --> python
     imgtool --> python
    @enduml