Implement cache

[s-dwinter]

Overview

Close #74. I implement a cache.

You can contol this feature throgh config file or command line option(default is false).

Valification

I am verifyring thiat running the example with option. I have confirmed that the execution time changes on the second and subsequent runs.

# first
❯ time ./dist/ysr_darwin_arm64/ysr template -c ./example/yashiro.yaml --enable-cache --cache-dir ./tmp ./example/example.yaml.tmpl
# This is a example of yashiro template.
---
apiVersion: v1
kind: Secret
...

./dist/ysr_darwin_arm64/ysr template -c ./example/yashiro.yaml --enable-cache  0.02s user 0.02s system 6% cpu 0.679 total

# cache file created
❯ la ./tmp                   
.key_hash  key  values

# second
❯ time ./dist/ysr_darwin_arm64/ysr template -c ./example/yashiro.yaml --enable-cache --cache-dir ./tmp ./example/example.yaml.tmpl
# This is a example of yashiro template.
---
apiVersion: v1
kind: Secret
...

./dist/ysr_darwin_arm64/ysr template -c ./example/yashiro.yaml --enable-cache  0.01s user 0.00s system 73% cpu 0.010 total

[s-dwinter]

Fix typo.