Update release notes for v2.4.7

Update release notes for v2.4.7.

Signed-off-by: David Enyeart <enyeart@us.ibm.com>

release_notes/v2.4.7.md

@@ -8,6 +8,17 @@ Fixes
 
 Return error for any unexpected nil conditions in gateway component to avoid nil pointer exceptions.
 
+**peer - Allow Hardware Security Module (HSM) configuration to be set with environment variables**
+
+The configuration parameters for the BCCSP PKCS11 component could not be set using environment variables.
+This fix ensures that configuration parameters can be set using environment variables, for example:
+```
+CORE_PEER_BCCSP_DEFAULT=PKCS11
+CORE_PEER_BCCSP_PKCS11_LIBRARY=/etc/hyperledger/fabric/libsofthsm2.so
+CORE_PEER_BCCSP_PKCS11_PIN=71811222
+CORE_PEER_BCCSP_PKCS11_LABEL=fabric
+```
+
 Improvements
 ------------