Fix file permissions

src/cdc_uart.c

diff --git a/src/cdc_uart.c b/src/cdc_uart.c
old mode 100755
new mode 100644

src/cdc_uart.h

diff --git a/src/cdc_uart.h b/src/cdc_uart.h
old mode 100755
new mode 100644

src/picoprobe_config.h

diff --git a/src/picoprobe_config.h b/src/picoprobe_config.h
old mode 100755
new mode 100644

src/probe.c

diff --git a/src/probe.c b/src/probe.c
old mode 100755
new mode 100644

src/probe.h

diff --git a/src/probe.h b/src/probe.h
old mode 100755
new mode 100644

src/probe.pio

diff --git a/src/probe.pio b/src/probe.pio
old mode 100755
new mode 100644