Version bump to 2.9.1 (issues platformio#639)

Version bump to 2.9.0 (issues platformio#438, platformio#472, platfor…

…mio#480, platformio#535, platformio#559, platformio#576, platformio#585, platformio#590, platformio#596, platformio#598, platformio#599, platformio#600, platformio#601, platformio#602, platformio#604, #609, platformio#610, platformio#613, platformio#616, platformio#618, platformio#626, platformio#627, platformio#631, platformio#632, platformio#633, platformio#635, platformio#636, platformio#637)

Version bump to 2.8.6 (issues platformio#568, platformio#571, platfor…

…mio#572, platformio#586, platformio#591)

Version bump to 2.8.5 (issues platformio#395, platformio#401, platfor…

…mio#523, platformio#526, platformio#527, platformio#528, platformio#534, platformio#536, platformio#540, platformio#541, platformio#543, platformio#544, platformio#550, platformio#552, platformio#555)

Version bump to 2.8.4 (issues platformio#494, platformio#501, platfor…

…mio#503, platformio#506, platformio#518)

Version bump to 2.8.3 (issue platformio#487)

Version bump to 2.8.2 (issue platformio#484)

Version bump to 2.8.0

Version bump to 2.8.0 (issues platformio#441, platformio#444, platfor…

…mio#447, platformio#453, platformio#458, platformio#465, platformio#470, platformio#474, platformio#476, platformio#483)

Version bump to 2.7.1 (issues platformio#356, platformio#421, platfor…

…mio#422, platformio#426, platformio#427, platformio#428, platformio#434)