Update 1.8.0

SX127x

• Sync with LoRaLib 8.2.0

CC1101

• Added option to use fixed packet length (by @phretor)
• Added promiscous mode (by @phretor)
• Added preamble length configuration (by @Guglio95)

RF69

• Added option to use fixed packet length (by @phretor)
• Added promiscous mode (by @phretor)

SX126x

• Fixed PA config (by @BarryPSmith)
• Optimized memory management (by @BarryPSmith)

And various bugfixes to examples.