Release FBPCF with version 1.0 (#157)

Summary:
Pull Request resolved: #157

((MAJOR))

We are releasing a major version, 1.0. Not only is this to test that our semantic versioning is working properly, but also this prepares us to release 2.0 sometime in the future.

Reviewed By: RuiyuZhu

Differential Revision: D35156895

fbshipit-source-id: dca5c9dde69aad7e12a2a63c40ab163489d7dd24

CHANGELOG.md

@@ -0,0 +1,8 @@
+# Change log
+All notable changes to this project will be documented in this file.
+
+## [1.0.0] - 2022-03-25
+- Official release of the v1 version of this repository.
+- This version only exposes APIs that depend on the emp-toolkit
+  and not on the newly built MPC engine.
+- Newer APIs that do not depend on emp are still in a pre-release stage.