Update requirements.txt with newer pySPF module

[reevesjeremy]

SPF Validation is failing for "nist.gov" on pySPF 2.0.11 with permanent error.

$ python trustymail nist.gov --spf --debug
2020-12-11 12:35:42,917 [nist.gov]
include: _spf1.nist.gov "None"
2020-12-11 12:35:43,762 [SPF] In check_spf_record at >>>\AppData\Local\Programs\Python\Python39\lib\site-packages\trustymail-0.7.5-py3.9.egg\trustymail\trustymail.py:335: SPF query returned permerror: SPF Permanent Error: No valid SPF record for included domain: _spf1.nist.gov: include:_spf1.nist.gov

Changing requirements.txt for pySPF to version 2.0.14 and reinstalling resolved the issue.

$ python trustymail nist.gov --spf --debug
2020-12-11 15:50:41,163 [nist.gov]
include: _spf1.nist.gov "v=spf1 include:spf.protection.outlook.com include:_spf.acquia.com include:_netblocks.google.com include:_netblocks2.google.com include:_netblocks3.google.com -all"
include: spf.protection.outlook.com "v=spf1 ip4:40.92.0.0/15 ip4:40.107.0.0/16 ip4:52.100.0.0/14 ip4:104.47.0.0/17 ip6:2a01:111:f400::/48 ip6:2a01:111:f403::/48 include:spfd.protection.outlook.com -all"
include: spfd.protection.outlook.com "v=spf1 ip4:51.4.72.0/24 ip4:51.5.72.0/24 ip4:51.5.80.0/27 ip4:51.4.80.0/27 ip6:2a01:4180:4051:0800::/64 ip6:2a01:4180:4050:0800::/64 ip6:2a01:4180:4051:0400::/64 ip6:2a01:4180:4050:0400::/64 -all"
include: _spf.acquia.com "v=spf1 ip4:67.23.31.6 ip4:173.203.56.127 ip4:67.207.158.35 ip4:173.203.81.82 ip4:173.203.79.77 ip4:67.207.158.141 ip4:173.203.82.6 -all"
include: _netblocks.google.com "v=spf1 ip4:35.190.247.0/24 ip4:64.233.160.0/19 ip4:66.102.0.0/20 ip4:66.249.80.0/20 ip4:72.14.192.0/18 ip4:74.125.0.0/16 ip4:108.177.8.0/21 ip4:173.194.0.0/16 ip4:209.85.128.0/17 ip4:216.58.192.0/19 ip4:216.239.32.0/19 ~all"
include: _netblocks2.google.com "v=spf1 ip6:2001:4860:4000::/36 ip6:2404:6800:4000::/36 ip6:2607:f8b0:4000::/36 ip6:2800:3f0:4000::/36 ip6:2a00:1450:4000::/36 ip6:2c0f:fb50:4000::/36 ~all"
include: _netblocks3.google.com "v=spf1 ip4:172.217.0.0/19 ip4:172.217.32.0/20 ip4:172.217.128.0/19 ip4:172.217.160.0/20 ip4:172.217.192.0/19 ip4:172.253.56.0/21 ip4:172.253.112.0/20 ip4:108.177.96.0/19 ip4:35.191.0.0/16 ip4:130.211.0.0/22 ~all"
include: _spf2.nist.gov "v=spf1 include:spf-0000c001.pphosted.com ip4:128.138.140.5 ip4:129.6.0.0/16 ip6:2610:20:6000::/37 -all"
include: spf-0000c001.pphosted.com "v=spf1 ip4:148.163.142.104 ip4:148.163.146.133"

Please update the requirements.txt file for public consumption. (Might take the opportunity to consider checking some other modules that may have released updates)