update changelog with secret changes and oauth2 support

CHANGELOG.md

@@ -7,6 +7,53 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Added keyring support, which means Himalaya can now use your
+  system's global keyring to get/set sensitive data like passwords or
+  tokens.
+- Added required IMAP option `imap-auth` and SMTP option
+  `smtp-auth`. Possible values: `passwd`, `oauth2`.
+- Added OAuth 2.0 support for IMAP and SMTP. To use it, set `imap-auth
+  = "oauth2"`. You also need these options:
+
+  - `imap-oauth2-method`
+  - `imap-oauth2-client-id`
+  - `imap-oauth2-client-secret` or `imap-oauth2-client-secret-cmd` or
+    `imap-oauth2-client-secret-keyring`
+  - `imap-oauth2-auth-url`
+  - `imap-oauth2-token-url`
+  - `imap-oauth2-access-token` or `imap-oauth2-access-token-cmd` or
+    `imap-oauth2-access-token-keyring`
+  - `imap-oauth2-refresh-token` or `imap-oauth2-refresh-token-cmd` or
+    `imap-oauth2-refresh-token-keyring`
+  - `imap-oauth2-scope` or `imap-oauth2-scopes`
+  - `imap-oauth2-pkce`
+
+### Changed
+
+- Changed the way secrets are managed. A secret is a sensitive data
+  like passwords or tokens. There is 3 possible ways to declare a
+  secret in the config file:
+
+  - `<key> = "secret-value"` for the raw secret (unsafe, not
+    recommanded),
+  - `<key>-cmd = "echo 'secret-value'"` for command that retrieve the
+    secret,
+  - `<key>-keyring = "keyring-entry"` for entry in your system's
+    global keyring that contains the secret.
+
+  This applies for:
+
+    - `imap-passwd`
+	- `imap-oauth2-client-secret`
+	- `imap-oauth2-access-token`
+	- `imap-oauth2-refresh-token`
+    - `smtp-passwd`
+	- `smtp-oauth2-client-secret`
+	- `smtp-oauth2-access-token`
+	- `smtp-oauth2-refresh-token`
+
 ## [0.7.3] - 2023-05-01
 
 ### Fixed