Downgrade zeroize_derive to version 0.7.0

This is required until BDK MSRV is changed to 1.51 or we replace
tiny-bip39 dependency.

Author: notmandatory

Cargo.toml

@@ -34,9 +34,10 @@ socks = { version = "0.3", optional = true }
 lazy_static = { version = "1.4", optional = true }
 tiny-bip39 = { version = "^0.8", optional = true }
 zeroize = { version = "<1.4.0", optional = true }
-# 1.2 broke something so fix this until https://github.com/maciejhirsz/tiny-bip39/pull/29 is merged.
-# (or we get rid of the tiny-bip39 dependency https://github.com/bitcoindevkit/bdk/issues/399)
-zeroize_derive = { version = "~1.1.0", optional = true }
+# the latest zeroize_derive 1.2 changed MSRV to 1.51 and our MSRV is 1.46, to fix this until we 
+# update our MSRV or get rid of the tiny-bip39 dependency https://github.com/bitcoindevkit/bdk/issues/399
+# we pin an older version
+zeroize_derive = { version = "~0.7.0", optional = true }
 bitcoinconsensus = { version = "0.19.0-3", optional = true }
 
 # Needed by bdk_blockchain_tests macro