build(deps): bump heapless from 0.5.6 to 0.6.1

Bumps [heapless](https://github.com/japaric/heapless) from 0.5.6 to 0.6.1.
- [Release notes](https://github.com/japaric/heapless/releases)
- [Changelog](https://github.com/japaric/heapless/blob/master/CHANGELOG.md)
- [Commits](https://github.com/japaric/heapless/compare/v0.5.6...v0.6.1)

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.lock

@@ -341,7 +341,6 @@ dependencies = [
  "as-slice",
  "generic-array 0.13.3",
  "hash32",
- "serde",
  "stable_deref_trait",
 ]
 
@@ -354,6 +353,7 @@ dependencies = [
  "as-slice",
  "generic-array 0.14.4",
  "hash32",
+ "serde",
  "stable_deref_trait",
 ]
 
@@ -728,7 +728,7 @@ dependencies = [
  "embedded-hal",
  "enum-iterator",
  "generic-array 0.14.4",
- "heapless 0.5.6",
+ "heapless 0.6.1",
  "log",
  "mcp23017",
  "miniconf",

Cargo.toml

@@ -34,7 +34,7 @@ cortex-m-log = { version = "0.7", features = ["log-integration"] }
 log = "0.4"
 panic-semihosting = { version = "0.5", optional = true }
 serde = { version = "1.0", features = ["derive"], default-features = false }
-heapless = { version = "0.5", features = ["serde"] }
+heapless = { version = "0.6", features = ["serde"] }
 cortex-m-rtic = "0.5.6"
 embedded-hal = "0.2.4"
 nb = "1.0.0"