notedeck_columns: use sha2 & base64

Signed-off-by: kernelkind <kernelkind@gmail.com>

crates/notedeck_columns/Cargo.toml

@@ -43,6 +43,8 @@ tracing-subscriber = { workspace = true }
 url = { workspace = true }
 urlencoding = { workspace = true }
 uuid = { workspace = true }
+sha2 = { workspace = true }
+base64 = { workspace = true }
 
 [dev-dependencies]
 tempfile = { workspace = true }