[chore] remove unused member from confmap.Resolver (open-telemetry#6489)

Signed-off-by: Bogdan <bogdandrutu@gmail.com>

.chloggen/confmapmu.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: confmap
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Remove unused public member `sync.Mutex` from `confmap.Resolver`.
+
+# One or more tracking issues or pull requests related to the change
+issues: [6489]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: This is an exception from the deprecation rule since this is not used anywhere and it is very unlikely that is used by external users.

confmap/resolver.go

@@ -20,7 +20,6 @@ import (
 	"fmt"
 	"regexp"
 	"strings"
-	"sync"
 
 	"go.uber.org/multierr"
 
@@ -57,7 +56,6 @@ type Resolver struct {
 	providers  map[string]Provider
 	converters []Converter
 
-	sync.Mutex
 	closers []CloseFunc
 	watcher chan error
 }