meta: updated messaging regarding dates

Currently our schedule specifies exact dates, this can be hard to
commit to. If we plan to be flexible with the dates we chose when
moving a release stream between different levels of support we should
be explicit about it.

This removes all future dates that have currently been decided,
alternatively offering a month in which the event will take place.

It also adds some new language the outlines when individuals should
expect us to give them a date.

 * No later than the first of the month the change is happening
 * No less than 14 days before the change is happening

I believe that this contract is reasonable and much less likely
to cause miscommunication in the future.

One thing not mentioned in here is how we will be communicating these
dates, and potential changes. We need to decide on a single communication
channel and stick to it. Very likely it can be the blog, but we should
discuss this first.

Author: MylesBorins

README.md

@@ -6,13 +6,13 @@
 |   :--:  |    :---:      |   :---:  |       :---:      |       :---:       |      :---:      |
 |  v0.10  |**End-of-Life**|    -     |        -         |    2015-10-01     |   2016-10-31    |
 |  v0.12  |**End-of-Life**|    -     |        -         |    2016-04-01     |   2016-12-31    |
-| [4.x][] |**Maintenance**| [Argon][]|    2015-10-01    |    2017-04-01     |   2018-04-01    |
+| [4.x][] |**Maintenance**| [Argon][]|    2015-10-01    |    2017-04-01     |   April 2018    |
 |  5.x    |No LTS         |          |                  |                   |                 |
-| [6.x][] |**Active**     | [Boron][]|    2016-10-18    |    2018-04-18     |   2019-04-18    |
+| [6.x][] |**Active**     | [Boron][]|    2016-10-18    |    April 2018     |   April 2019    |
 |  7.x    |No LTS         |          |                  |                   |                 |
-|  8.x    |**Pending**    | Pending  |    2017-10-01    |    2019-04-01     |   2019-12-31<sup>2</sup> |
+|  8.x    |**Pending**    | Pending  |    October 2017  |    April 2019     |   December 2019<sup>2</sup> |
 |  9.x    |No LTS         |          |                  |                   |                 |
-| 10.x    |**Pending**    | Pending  |    2018-10-01    |    2020-04-01     |   2021-04-01    |
+| 10.x    |**Pending**    | Pending  |    October 2018  |    April 2020     |   April 2021    |
 
 * <sup>1</sup>: All scheduled dates are subject to change by the Node.js LTS
   working group or Node.js Core Technical Committee.
@@ -40,6 +40,10 @@ period of 18 months from the date it enters LTS coverage. Following those 18
 months of active support, the major version will transition into "maintenance"
 mode for 12 additional months.
 
+The exact date that a release stream will be moved to LTS, moved between LTS
+modes, or deprecated will will be chosen no later than the first day of the month.
+If it is to be changed, it will be done with no less than 14 days notice.
+
 Given this schedule, there will be no more than two active LTS releases at any
 given time, overlapping for a maximum period of six months.