use 115200 baud and print panic over serial

Cargo.lock

@@ -32,7 +32,7 @@ dependencies = [
  "arduino-hal",
  "embedded-hal 1.0.0",
  "nb 1.1.0",
- "panic-halt",
+ "panic-serial",
  "proc-macro2",
  "ufmt",
 ]
@@ -142,10 +142,13 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"
 
 [[package]]
-name = "panic-halt"
-version = "0.2.0"
+name = "panic-serial"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de96540e0ebde571dc55c73d60ef407c653844e6f9a1e2fdbd40c07b9252d812"
+checksum = "c3afc60d58b0825ea32dd8d8a2796098f7b87ad3b9392cace3b6dc79e450afd9"
+dependencies = [
+ "ufmt",
+]
 
 [[package]]
 name = "paste"