Cargo.toml: Add a note about base64

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/Cargo.toml b/Cargo.toml
index aab518199066b8bf6c9b5fcc9f2d2cbf81f7f316..b75e7110445d133ee49d013ab803f0d5f4f5992b 100644 (file)
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -30,7 +30,7 @@ hippotat-macros = { version = "1.0.0", path = "macros" }
 # versions specified here are mostly just guesses at what is needed
 # (or currently available):
 backtrace = "0.3"
-base64 = "0.13"
+base64 = "0.13" # 0.20 has substantially incompatible API
 clap = { version = "3", features = ["derive"] }
 easy-ext = "1"
 educe = "0.4"