Prometheus php-fpm exporter

notes:

We need this exporter until this bug is fixed

Release list
2.2.0	2022-05-20 1y+
2.1.0	2022-05-20 1y+
2.0.4	2021-11-04 1y+
2.0.3	2021-08-27 1y+
2.0.2	2021-05-10 1y+
2.0.1	2021-01-07 1y+
2.0.0	2020-11-22 1y+
1.2.1	2020-11-02 1y+
1.1.1	2020-03-21 1y+
1.1.0	2020-03-10 1y+
1.0.0	2018-12-30 1y+
0.5.3	2018-12-29 1y+
0.5.2	2018-06-26 1y+
0.5.1	2018-06-26 1y+
0.5.0: Implement unix socket support and make status path configurable (#23)	2018-03-18 1y+
0.4.1 - Fix: Swapped `start since` / `accepted conenctions`	2018-03-05 1y+
0.4.0	2018-03-01 1y+
0.3.1	2018-02-28 1y+
0.3.0	2018-02-28 1y+
0.2.0 – Calculate correct idle/active/total processes	2018-02-25 1y+

notes:

We need this exporter until this bug is fixed

Release notes:

2.1.0 (2022-05-20)

Revert "chore: add build target to Makefile & builder to Dockerfile" (#218) (7004aa2), closes #218 #215