docs: update build tool prerequisites

Bump `dtc`, `clang` and `sphinx` to reconcile our minimum requirements
with the versions used in CI.

Change-Id: Ia848b4bdd93dc833ea03eda5b002561468042f52
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/docs/getting_started/prerequisites.rst b/docs/getting_started/prerequisites.rst
index dea1825..c414b1f 100644
--- a/docs/getting_started/prerequisites.rst
+++ b/docs/getting_started/prerequisites.rst
@@ -28,15 +28,15 @@
 ======================== =====================
 Arm Compiler             6.18
 Arm GNU Compiler         13.3
-Clang/LLVM               11.0.0
-Device Tree Compiler     1.4.7
+Clang/LLVM               18.1.8
+Device Tree Compiler     1.6.1
 GNU make                 3.81
 mbed TLS\ [#f1]_         3.6.1
 Node.js [#f2]_           16
 OpenSSL                  1.0.0
 Poetry                   1.3.2
 QCBOR\ [#f3]_            1.2
-Sphinx\ [#f2]_           2.4.4
+Sphinx\ [#f2]_           5.3.0
 ======================== =====================
 
 .. [#f1] Required for Trusted Board Boot and Measured Boot.