chore: reformat changelog to follow KeepAChangelog standard (#50)

Author: cakepietoast

Diff for: CHANGELOG.md

@@ -1,38 +1,34 @@
-# HISTORY 
+# Changelog 
+All notable changes to this project will be documented in this file.
 
-## May 29th
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-**0.9.4**
+## [Unreleased]
 
-* **Metrics**: Bugfix - Metrics were not correctly flushed, and cleared on every invocation
+## [0.9.4] - 2020-05-29
+### Fixed
+- **Metrics**: Fix issue where metrics were not correctly flushed, and cleared on every invocation
 
-## May 16th
+## [0.9.3] - 2020-05-16
+### Fixed
+- **Tracer**: Fix Runtime Error for nested sync due to incorrect loop usage
 
-**0.9.3**
+## [0.9.2] - 2020-05-14
+### Fixed
+- **Tracer**: Import aiohttp lazily so it's not a hard dependency
 
-* **Tracer**: Bugfix - Runtime Error for nested sync due to incorrect loop usage
-
-## May 14th
-
-**0.9.2**
-
-* **Tracer**: Bugfix - aiohttp lazy import so it's not a hard dependency
-
-## May 12th
-
-**0.9.0**
-
-* **Tracer**: Support for async functions in `Tracer` via `capture_method` decorator
-* **Tracer**: Support for `aiohttp` via `aiohttp_trace_config` trace config
-* **Tracer**: Support for patching specific modules via `patch_modules` param
-* **Tracer**: Document escape hatch mechanisms via `tracer.provider`
-
-## May 1st
-
-**0.8.1**
+## [0.9.0] - 2020-05-12
+### Added
+- **Tracer**: Support for async functions in `Tracer` via `capture_method` decorator
+- **Tracer**: Support for `aiohttp` via `aiohttp_trace_config` trace config
+- **Tracer**: Support for patching specific modules via `patch_modules` param
+- **Tracer**: Document escape hatch mechanisms via `tracer.provider`
 
+## [0.8.1] - 2020-05-1
+### Fixed
 * **Metrics**: Fix metric unit casting logic if one passes plain string (value or key)
-* **Metrics: **Fix `MetricUnit` enum values for
+* **Metrics:**: Fix `MetricUnit` enum values for
     - `BytesPerSecond`
     - `KilobytesPerSecond`
     - `MegabytesPerSecond`
@@ -45,40 +41,36 @@
     - `TerabitsPerSecond`
     - `CountPerSecond`
 
-## April 24th
-
-**0.8.0**
-
-* **Logger**: Introduces `Logger` class for stuctured logging as a replacement for `logger_setup`
-* **Logger**: Introduces `Logger.inject_lambda_context` decorator as a replacement for `logger_inject_lambda_context`
-* **Logger**: Raise `DeprecationWarning` exception for both `logger_setup`, `logger_inject_lambda_context`
-
-## April 20th, 2020
-
-**0.7.0**
-
-* **Middleware factory**: Introduces Middleware Factory to build your own middleware via `lambda_handler_decorator`
-* **Metrics**: Fixes metrics dimensions not being included correctly in EMF
-
-## April 9th, 2020
-
-**0.6.3**
-
-* **Logger**: Fix `log_metrics` decorator logic not calling the decorated function, and exception handling
+## [0.8.0] - 2020-04-24
+### Added
+- **Logger**: Introduced `Logger` class for stuctured logging as a replacement for `logger_setup`
+- **Logger**: Introduced `Logger.inject_lambda_context` decorator as a replacement for `logger_inject_lambda_context`
 
-## April 8th, 2020
+### Removed
+- **Logger**: Raise `DeprecationWarning` exception for both `logger_setup`, `logger_inject_lambda_context`
 
-**0.6.1**
+## [0.7.0] - 2020-04-20
+### Added
+- **Middleware factory**: Introduced Middleware Factory to build your own middleware via `lambda_handler_decorator`
 
-* **Metrics**: Introduces Metrics middleware to utilise CloudWatch Embedded Metric Format
-* **Metrics**: Adds deprecation warning for `log_metrics`
+### Fixed
+- **Metrics**: Fixed metrics dimensions not being included correctly in EMF
 
-## February 20th, 2020
+## [0.6.3] - 2020-04-09
+### Fixed
+- **Logger**: Fix `log_metrics` decorator logic not calling the decorated function, and exception handling
 
-**0.5.0**
+## [0.6.1] - 2020-04-08
+### Added
+- **Metrics**: Introduces Metrics middleware to utilise CloudWatch Embedded Metric Format
 
-* **Logger**: Introduces log sampling for debug - Thanks to [Danilo's contribution](https://github.com/awslabs/aws-lambda-powertools/pull/7)
+### Deprecated
+- **Metrics**: Added deprecation warning for `log_metrics`
 
-## November 15th, 2019 
+## [0.5.0] - 2020-02-20
+### Added
+- **Logger**: Introduced log sampling for debug - Thanks to [Danilo's contribution](https://github.com/awslabs/aws-lambda-powertools/pull/7)
 
-* Public beta release
+## [0.1.0] - 2019-11-15
+### Added
+- Public beta release