config v6 support - Githubissues

Implements config v6 support.

Features/improvements:

[x] Fetch new config json version (config_v6.json) and update config model
[x] SDK key format validation (when client is not set up to use local-only flag overrides)
[x] AND conditions
[x] New condition types
- Prerequisite flag condition
- Segment condition
[x] Changed comparison operators
- (NOT) CONTAINS ANY OF
[x] New comparison operators
- BEFORE/AFTER
- TEXT (NOT) EQUALS (both hashed and cleartext)
- TEXT (NOT) STARTS/ENDS WITH ANY OF (both hashed and cleartext)
- ARRAY CONTAINS ANY OF (both hashed and cleartext)
[x] Percentage options within targeting rules
[x] Percentage options based on custom attributes
[x] Custom User Object attribute handling (don't force string values + autoconversions under the hood)
[x] User Object attribute/comparison value trimming
[x] Comparison value hashing changes (SHA256, salting)
[x] Flag overrides vs. config json salt and segments
[x] EvaluationDetails.matched_targeting_rule/matched_percentage_option properties (rename + set combinations correctly)
[x] Update ConfigCatClient.getKeyAndValue

Tests:

[x] Update cache key/payload tests
[x] Evaluation matrix tests
- Config v1 features (both V1 & V2)
- Config v2 features
[x] Evaluation log tests
[x] SDK key format validation
[x] Custom User Object attribute handling (don't force string values + autoconversions under the hood)
[x] Flag overrides vs. prerequisite flags (circular dependency, comparison value type mismatch, dependent/prereq flag overriding)
[x] Flag overrides vs. config json salt and segments
[x] EvaluationDetails.matched_targeting_rule/matched_percentage_option properties (rename + set combinations correctly)
[x] Special character tests (https://trello.com/c/qh4jHrvm)
[x] Comparison attribute and comparison value trimming tests (https://trello.com/c/vt8FFrSZ)
[x] Comparison attribute conversion to canonical string representation tests (https://trello.com/c/CZgGrrcb)

Related improvements/fixes:

[x] Dynamically typed languages should log a warning when default value doesn't match the setting type (see https://trello.com/c/Le6vimGu)
[x] We should go to the cache in all polling modes instead of using the in memory variable (see https://trello.com/c/rreKm64A)
[x] Improve message of log event 1103 (https://trello.com/c/Mb7rvm64)

configcat / ruby-sdk