Replace deprecated `error_chain` crate with `anyhow` (#1405)

The `error_chain` crate is now deprecated for a long time and `anyhow`
has proven to be a popular replacement for applications.

This also improves the current error messages for panics.

```
PAGER='"less' git show
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: \
Error(Msg("Could not parse pager command."), State { next_error: Some(ParseError), \
backtrace: InternalBacktrace })', src/main.rs:136:88
```

```
PAGER='"less' git show
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Could not parse pager command.

Caused by:
    missing closing quote', src/main.rs:125:88
```

1 files changed, 1 insertions, 5 deletions

diff --git a/Cargo.toml b/Cargo.toml
index fb75c24d..37b1c79a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,6 +20,7 @@ chrono = "0.4.23"
 chrono-humanize = "0.2.2"
 ansi_colours = "1.2.1"
 ansi_term = "0.12.1"
+anyhow = "1.0.70"
 atty = "0.2.14"
 bitflags = "2.2.1"
 box_drawing = "0.1.2"
@@ -55,10 +56,5 @@ version = "0.28.2"
 default-features = false
 features = []
 
-[dependencies.error-chain]
-version = "0.12.4"
-default-features = false
-features = []
-
 [profile.test]
 opt-level = 2